Standard Reference Data

<!DOCTYPE html> <html lang="en" dir="ltr" prefix="content: http://purl.org/rss/1.0/modules/content/ dc: http://purl.org/dc/terms/ foaf: http://xmlns.com/foaf/0.1/ og: http://ogp.me/ns# rdfs: http://www.w3.org/2000/01/rdf-schema# schema: http://schema.org/ sioc: http://rdfs.org/sioc/ns# sioct: http://rdfs.org/sioc/types# skos: http://www.w3.org/2004/02/skos/core# xsd: http://www.w3.org/2001/XMLSchema# "> <head><script type="text/javascript" src="/_static/js/bundle-playback.js?v=HxkREWBo" charset="utf-8"></script> <script type="text/javascript" src="/_static/js/wombat.js?v=txqj7nKC" charset="utf-8"></script> <script>window.RufflePlayer=window.RufflePlayer||{};window.RufflePlayer.config={"autoplay":"on","unmuteOverlay":"hidden"};</script> <script type="text/javascript" src="/_static/js/ruffle/ruffle.js"></script> <script type="text/javascript"> __wm.init("https://web.archive.org/web"); __wm.wombat("https://www.nist.gov/srd","20230314214432","https://web.archive.org/","web","/_static/", "1678830272"); </script> <link rel="stylesheet" type="text/css" href="/_static/css/banner-styles.css?v=S1zqJCYt" /> <link rel="stylesheet" type="text/css" href="/_static/css/iconochive.css?v=3PDvdIFv" />  <meta charset="utf-8"/><script type="text/javascript">(window.NREUM||(NREUM={})).init={ajax:{deny_list:["gov-bam.nr-data.net"]}};(window.NREUM||(NREUM={})).loader_config={licenseKey:"37b7ccb661",applicationID:"1089704227"};;(()=>{var e,t,r={9071:(e,t,r)=>{"use strict";r.d(t,{I:()=>n});var n=0,i=navigator.userAgent.match(/Firefox[\/\s](\d+\.\d+)/);i&&(n=+i[1])},6562:(e,t,r)=>{"use strict";r.d(t,{P_:()=>v,Mt:()=>h,C5:()=>d,DL:()=>y,OP:()=>R,lF:()=>L,Yu:()=>A,Dg:()=>p,CX:()=>f,GE:()=>w,sU:()=>M});var n={};r.r(n),r.d(n,{agent:()=>x,match:()=>O,version:()=>T});var i=r(6797),o=r(909),a=r(8610);class s{constructor(e,t){try{if(!e||"object"!=typeof e)return(0,a.Z)("New setting a Configurable requires an object as input");if(!t||"object"!=typeof t)return(0,a.Z)("Setting a Configurable requires a model to set its initial properties");Object.assign(this,t),Object.entries(e).forEach((e=>{let[t,r]=e;const n=(0,o.q)(t);n.length&&r&&"object"==typeof r&&n.forEach((e=>{e in r&&((0,a.Z)('"'.concat(e,'" is a protected attribute and can not be changed in feature ').concat(t,". It will have no effect.")),delete r[e])})),this[t]=r}))}catch(e){(0,a.Z)("An error occured while setting a Configurable",e)}}}const c={beacon:i.ce.beacon,errorBeacon:i.ce.errorBeacon,licenseKey:void 0,applicationID:void 0,sa:void 0,queueTime:void 0,applicationTime:void 0,ttGuid:void 0,user:void 0,account:void 0,product:void 0,extra:void 0,jsAttributes:{},userAttributes:void 0,atts:void 0,transactionName:void 0,tNamePlain:void 0},u={};function d(e){if(!e)throw new Error("All info objects require an agent identifier!");if(!u[e])throw new Error("Info for ".concat(e," was never set"));return u[e]}function f(e,t){if(!e)throw new Error("All info objects require an agent identifier!");u[e]=new s(t,c),(0,i.Qy)(e,u[e],"info")}const l={allow_bfcache:!0,privacy:{cookies_enabled:!0},ajax:{deny_list:void 0,enabled:!0,harvestTimeSeconds:10},distributed_tracing:{enabled:void 0,exclude_newrelic_header:void 0,cors_use_newrelic_header:void 0,cors_use_tracecontext_headers:void 0,allowed_origins:void 0},ssl:void 0,obfuscate:void 0,jserrors:{enabled:!0,harvestTimeSeconds:10},metrics:{enabled:!0},page_action:{enabled:!0,harvestTimeSeconds:30},page_view_event:{enabled:!0},page_view_timing:{enabled:!0,harvestTimeSeconds:30,long_task:!1},session_trace:{enabled:!0,harvestTimeSeconds:10},spa:{enabled:!0,harvestTimeSeconds:10}},g={};function v(e){if(!e)throw new Error("All configuration objects require an agent identifier!");if(!g[e])throw new Error("Configuration for ".concat(e," was never set"));return g[e]}function p(e,t){if(!e)throw new Error("All configuration objects require an agent identifier!");g[e]=new s(t,l),(0,i.Qy)(e,g[e],"config")}function h(e,t){if(!e)throw new Error("All configuration objects require an agent identifier!");var r=v(e);if(r){for(var n=t.split("."),i=0;i<n.length-1;i++)if("object"!=typeof(r=r[n[i]]))return;r=r[n[n.length-1]]}return r}const m={accountID:void 0,trustKey:void 0,agentID:void 0,licenseKey:void 0,applicationID:void 0,xpid:void 0},b={};function y(e){if(!e)throw new Error("All loader-config objects require an agent identifier!");if(!b[e])throw new Error("LoaderConfig for ".concat(e," was never set"));return b[e]}function w(e,t){if(!e)throw new Error("All loader-config objects require an agent identifier!");b[e]=new s(t,m),(0,i.Qy)(e,b[e],"loader_config")}const A=(0,i.mF)().o;var E=r(2053),x=null,T=null;if(navigator.userAgent){var _=navigator.userAgent,D=_.match(/Version\/(\S+)\s+Safari/);D&&-1===_.indexOf("Chrome")&&-1===_.indexOf("Chromium")&&(x="Safari",T=D[1])}function O(e,t){if(!x)return!1;if(e!==x)return!1;if(!t)return!0;if(!T)return!1;for(var r=T.split("."),n=t.split("."),i=0;i<n.length;i++)if(n[i]!==r[i])return!1;return!0}var j=r(5526),k=r(2374);const P="NRBA_SESSION_ID";function S(){if(!k.il)return null;try{let e;return null===(e=window.sessionStorage.getItem(P))&&(e=(0,j.ky)(16),window.sessionStorage.setItem(P,e)),e}catch(e){return null}}var I=r(8226);const C=e=>({customTransaction:void 0,disabled:!1,isolatedBacklog:!1,loaderType:void 0,maxBytes:3e4,offset:(0,E.yf)(),onerror:void 0,origin:""+k._A.location,ptid:void 0,releaseIds:{},sessionId:1==h(e,"privacy.cookies_enabled")?S():null,xhrWrappable:"function"==typeof k._A.XMLHttpRequest?.prototype?.addEventListener,userAgent:n,version:I.q}),N={};function R(e){if(!e)throw new Error("All runtime objects require an agent identifier!");if(!N[e])throw new Error("Runtime for ".concat(e," was never set"));return N[e]}function M(e,t){if(!e)throw new Error("All runtime objects require an agent identifier!");N[e]=new s(t,C(e)),(0,i.Qy)(e,N[e],"runtime")}function L(e){return function(e){try{const t=d(e);return!!t.licenseKey&&!!t.errorBeacon&&!!t.applicationID}catch(e){return!1}}(e)}},8226:(e,t,r)=>{"use strict";r.d(t,{q:()=>n});const n="1227.PROD"},9557:(e,t,r)=>{"use strict";r.d(t,{w:()=>o});var n=r(8610);const i={agentIdentifier:""};class o{constructor(e){try{if("object"!=typeof e)return(0,n.Z)("shared context requires an object as input");this.sharedContext={},Object.assign(this.sharedContext,i),Object.entries(e).forEach((e=>{let[t,r]=e;Object.keys(i).includes(t)&&(this.sharedContext[t]=r)}))}catch(e){(0,n.Z)("An error occured while setting SharedContext",e)}}}},4329:(e,t,r)=>{"use strict";r.d(t,{L:()=>d,R:()=>c});var n=r(3752),i=r(7022),o=r(4045),a=r(2325);const s={};function c(e,t){const r={staged:!1,priority:a.p[t]||0};u(e),s[e].get(t)||s[e].set(t,r)}function u(e){e&&(s[e]||(s[e]=new Map))}function d(){let e=arguments.length>0&&void 0!==arguments[0]?arguments[0]:"",t=arguments.length>1&&void 0!==arguments[1]?arguments[1]:"feature";if(u(e),!e||!s[e].get(t))return a(t);s[e].get(t).staged=!0;const r=Array.from(s[e]);function a(t){const r=e?n.ee.get(e):n.ee,a=o.X.handlers;if(r.backlog&&a){var s=r.backlog[t],c=a[t];if(c){for(var u=0;s&&u<s.length;++u)f(s[u],c);(0,i.D)(c,(function(e,t){(0,i.D)(t,(function(t,r){r[0].on(e,r[1])}))}))}delete a[t],r.backlog[t]=null,r.emit("drain-"+t,[])}}r.every((e=>{let[t,r]=e;return r.staged}))&&(r.sort(((e,t)=>e[1].priority-t[1].priority)),r.forEach((e=>{let[t]=e;a(t)})))}function f(e,t){var r=e[1];(0,i.D)(t[r],(function(t,r){var n=e[0];if(r[0]===n){var i=r[1],o=e[3],a=e[2];i.apply(o,a)}}))}},3752:(e,t,r)=>{"use strict";r.d(t,{ee:()=>u});var n=r(6797),i=r(3916),o=r(7022),a=r(6562),s="nr@context";let c=(0,n.fP)();var u;function d(){}function f(){return new d}function l(){u.aborted=!0,u.backlog={}}c.ee?u=c.ee:(u=function e(t,r){var n={},c={},g={},v=!1;try{v=16===r.length&&(0,a.OP)(r).isolatedBacklog}catch(e){}var p={on:b,addEventListener:b,removeEventListener:y,emit:m,get:A,listeners:w,context:h,buffer:E,abort:l,aborted:!1,isBuffering:x,debugId:r,backlog:v?{}:t&&"object"==typeof t.backlog?t.backlog:{}};return p;function h(e){return e&&e instanceof d?e:e?(0,i.X)(e,s,f):f()}function m(e,r,n,i,o){if(!1!==o&&(o=!0),!u.aborted||i){t&&o&&t.emit(e,r,n);for(var a=h(n),s=w(e),d=s.length,f=0;f<d;f++)s[f].apply(a,r);var l=T()[c[e]];return l&&l.push([p,e,r,a]),a}}function b(e,t){n[e]=w(e).concat(t)}function y(e,t){var r=n[e];if(r)for(var i=0;i<r.length;i++)r[i]===t&&r.splice(i,1)}function w(e){return n[e]||[]}function A(t){return g[t]=g[t]||e(p,t)}function E(e,t){var r=T();p.aborted||(0,o.D)(e,(function(e,n){t=t||"feature",c[n]=t,t in r||(r[t]=[])}))}function x(e){return!!T()[c[e]]}function T(){return p.backlog}}(void 0,"globalEE"),c.ee=u)},9252:(e,t,r)=>{"use strict";r.d(t,{E:()=>n,p:()=>i});var n=r(3752).ee.get("handle");function i(e,t,r,i,o){o?(o.buffer([e],i),o.emit(e,t,r)):(n.buffer([e],i),n.emit(e,t,r))}},4045:(e,t,r)=>{"use strict";r.d(t,{X:()=>o});var n=r(9252);o.on=a;var i=o.handlers={};function o(e,t,r,o){a(o||n.E,i,e,t,r)}function a(e,t,r,i,o){o||(o="feature"),e||(e=n.E);var a=t[o]=t[o]||{};(a[r]=a[r]||[]).push([e,i])}},8544:(e,t,r)=>{"use strict";r.d(t,{bP:()=>s,iz:()=>c,m$:()=>a});var n=r(2374);let i=!1,o=!1;try{const e={get passive(){return i=!0,!1},get signal(){return o=!0,!1}};n._A.addEventListener("test",null,e),n._A.removeEventListener("test",null,e)}catch(e){}function a(e,t){return i||o?{capture:!!e,passive:i,signal:t}:!!e}function s(e,t){let r=arguments.length>2&&void 0!==arguments[2]&&arguments[2];window.addEventListener(e,t,a(r))}function c(e,t){let r=arguments.length>2&&void 0!==arguments[2]&&arguments[2];document.addEventListener(e,t,a(r))}},5526:(e,t,r)=>{"use strict";r.d(t,{Rl:()=>i,ky:()=>o});var n=r(2374);function i(){var e=null,t=0,r=n._A?.crypto||n._A?.msCrypto;function i(){return e?15&e[t++]:16*Math.random()|0}r&&r.getRandomValues&&(e=r.getRandomValues(new Uint8Array(31)));for(var o,a="xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx",s="",c=0;c<a.length;c++)s+="x"===(o=a[c])?i().toString(16):"y"===o?(o=3&i()|8).toString(16):o;return s}function o(e){var t=null,r=0,n=self.crypto||self.msCrypto;n&&n.getRandomValues&&Uint8Array&&(t=n.getRandomValues(new Uint8Array(31)));for(var i=[],o=0;o<e;o++)i.push(a().toString(16));return i.join("");function a(){return t?15&t[r++]:16*Math.random()|0}}},2053:(e,t,r)=>{"use strict";r.d(t,{nb:()=>s,os:()=>c,yf:()=>a,zO:()=>o});var n=(new Date).getTime(),i=n;function o(){return performance?.now?Math.round(performance.now()):(n=Math.max((new Date).getTime(),n))-i}function a(){return n}function s(e){i=e}function c(){return i}},6625:(e,t,r)=>{"use strict";r.d(t,{s:()=>a,v:()=>s});var n=r(8283),i=r(2053),o=r(2374);let a=!0;function s(e){var t=function(){a=!1;const e=o._A?.performance?.timeOrigin||o._A?.performance?.timing?.navigationStart;if(!e)return;return Math.round(e)}();t&&((0,n.B)(e,"starttime",t),(0,i.nb)(t))}},8283:(e,t,r)=>{"use strict";r.d(t,{B:()=>o,L:()=>a});var n=r(2053),i={};function o(e,t,r){void 0===r&&(r=(0,n.zO)()+(0,n.os)()),i[e]=i[e]||{},i[e][t]=r}function a(e,t,r,n){const o=e.sharedContext.agentIdentifier;var a=i[o]?.[r],s=i[o]?.[n];void 0!==a&&void 0!==s&&e.store("measures",t,{value:s-a})}},2545:(e,t,r)=>{"use strict";r.d(t,{L:()=>c});var n=r(9071),i=r(8544),o=r(8305),a=r(2374),s=r(6998);if(a.v6){a._A.cleanupTasks=[];const e=a._A.close;a._A.close=()=>{for(let e of a._A.cleanupTasks)e();e()}}function c(e,t){if(a.il)if(t)(0,s.N)(e,!0),(0,i.bP)("pagehide",e);else{var r=(0,o.Z)(e);!n.I||navigator.sendBeacon?(0,i.bP)("pagehide",r):(0,i.bP)("beforeunload",r),(0,i.bP)("unload",r)}else a.v6&&a._A.cleanupTasks.push(e)}},8610:(e,t,r)=>{"use strict";function n(e,t){console&&console.warn&&"function"==typeof console.warn&&(console.warn("New Relic: ".concat(e)),t&&console.warn(t))}r.d(t,{Z:()=>n})},3916:(e,t,r)=>{"use strict";r.d(t,{X:()=>i});var n=Object.prototype.hasOwnProperty;function i(e,t,r){if(n.call(e,t))return e[t];var i=r();if(Object.defineProperty&&Object.keys)try{return Object.defineProperty(e,t,{value:i,writable:!0,enumerable:!1}),i}catch(e){}return e[t]=i,i}},2374:(e,t,r)=>{"use strict";r.d(t,{_A:()=>o,il:()=>n,lW:()=>a,v6:()=>i});const n=Boolean("undefined"!=typeof window&&window.document),i=Boolean("undefined"!=typeof WorkerGlobalScope&&self.navigator instanceof WorkerNavigator);let o=(()=>{if(n)return window;if(i){if("undefined"!=typeof globalThis&&globalThis instanceof WorkerGlobalScope)return globalThis;if(self instanceof WorkerGlobalScope)return self}throw new Error('New Relic browser agent shutting down due to error: Unable to locate global scope. This is possibly due to code redefining browser global variables like "self" and "window".')})();function a(){return o}},7022:(e,t,r)=>{"use strict";r.d(t,{D:()=>i});var n=Object.prototype.hasOwnProperty;function i(e,t){var r=[],i="",o=0;for(i in e)n.call(e,i)&&(r[o]=t(i,e[i]),o+=1);return r}},8305:(e,t,r)=>{"use strict";r.d(t,{Z:()=>o});var n=r(8683),i=r.n(n);function o(e){var t,r=!1;return function(){return r?t:(r=!0,t=e.apply(this,i()(arguments)))}}},2650:(e,t,r)=>{"use strict";r.d(t,{K:()=>a,b:()=>o});var n=r(8544);function i(){return"undefined"==typeof document||"complete"===document.readyState}function o(e,t){if(i())return e();(0,n.bP)("load",e,t)}function a(e){if(i())return e();(0,n.iz)("DOMContentLoaded",e)}},6797:(e,t,r)=>{"use strict";r.d(t,{EZ:()=>u,Qy:()=>c,ce:()=>o,fP:()=>a,gG:()=>d,mF:()=>s});var n=r(2053),i=r(2374);const o={beacon:"bam.nr-data.net",errorBeacon:"bam.nr-data.net"};function a(){return i._A.NREUM||(i._A.NREUM={}),void 0===i._A.newrelic&&(i._A.newrelic=i._A.NREUM),i._A.NREUM}function s(){let e=a();return e.o||(e.o={ST:i._A.setTimeout,SI:i._A.setImmediate,CT:i._A.clearTimeout,XHR:i._A.XMLHttpRequest,REQ:i._A.Request,EV:i._A.Event,PR:i._A.Promise,MO:i._A.MutationObserver,FETCH:i._A.fetch}),e}function c(e,t,r){let i=a();const o=i.initializedAgents||{},s=o[e]||{};return Object.keys(s).length||(s.initializedAt={ms:(0,n.zO)(),date:new Date}),i.initializedAgents={...o,[e]:{...s,[r]:t}},i}function u(e,t){a()[e]=t}function d(){return function(){let e=a();const t=e.info||{};e.info={beacon:o.beacon,errorBeacon:o.errorBeacon,...t}}(),function(){let e=a();const t=e.init||{};e.init={...t}}(),s(),function(){let e=a();const t=e.loader_config||{};e.loader_config={...t}}(),a()}},6998:(e,t,r)=>{"use strict";r.d(t,{N:()=>i,e:()=>o});var n=r(8544);function i(e){let t=arguments.length>1&&void 0!==arguments[1]&&arguments[1];return void(0,n.iz)("visibilitychange",(function(){if(t){if("hidden"!=document.visibilityState)return;e()}e(document.visibilityState)}))}function o(){return"hidden"===document.visibilityState?-1:1/0}},6034:(e,t,r)=>{"use strict";r.d(t,{gF:()=>o,mY:()=>i,t9:()=>n,vz:()=>s,xS:()=>a});const n=r(2325).D.metrics,i="sm",o="cm",a="storeSupportabilityMetrics",s="storeEventMetrics"},2484:(e,t,r)=>{"use strict";r.d(t,{t:()=>n});const n=r(2325).D.pageViewEvent},6382:(e,t,r)=>{"use strict";r.d(t,{t:()=>n});const n=r(2325).D.pageViewTiming},1509:(e,t,r)=>{"use strict";r.d(t,{W:()=>s});var n=r(6562),i=r(3752),o=r(2384),a=r(6797);class s{constructor(e,t,r){this.agentIdentifier=e,this.aggregator=t,this.ee=i.ee.get(e,(0,n.OP)(this.agentIdentifier).isolatedBacklog),this.featureName=r,this.blocked=!1,this.checkConfiguration()}checkConfiguration(){if(!(0,n.lF)(this.agentIdentifier)){let e={...(0,a.gG)().info?.jsAttributes};try{e={...e,...(0,n.C5)(this.agentIdentifier)?.jsAttributes}}catch(e){}(0,o.j)(this.agentIdentifier,{...(0,a.gG)(),info:{...(0,a.gG)().info,jsAttributes:e}})}}}},2384:(e,t,r)=>{"use strict";r.d(t,{j:()=>w});var n=r(8683),i=r.n(n),o=r(2325),a=r(6562),s=r(9252),c=r(7022),u=r(3752),d=r(2053),f=r(4329),l=r(2650),g=r(2374),v=r(8610),p=r(6034);function h(e){["setErrorHandler","finished","addToTrace","inlineHit","addRelease","addPageAction","setCurrentRouteName","setPageViewName","setCustomAttribute","interaction","noticeError"].forEach((t=>{e[t]=function(){for(var r=arguments.length,n=new Array(r),i=0;i<r;i++)n[i]=arguments[i];return function(t){for(var r=arguments.length,n=new Array(r>1?r-1:0),i=1;i<r;i++)n[i-1]=arguments[i];Object.values(e.initializedAgents).forEach((e=>{e.exposed&&e.api[t]&&e.api[t](...n)}))}(t,...n)}}))}var m=r(6797);const b={stn:[o.D.sessionTrace],err:[o.D.jserrors,o.D.metrics],ins:[o.D.pageAction],spa:[o.D.spa]};const y={};function w(e){let t=arguments.length>1&&void 0!==arguments[1]?arguments[1]:{},n=arguments.length>2?arguments[2]:void 0,w=arguments.length>3?arguments[3]:void 0,{init:A,info:E,loader_config:x,runtime:T={loaderType:n},exposed:_=!0}=t;const D=(0,m.gG)();let O={};return E||(A=D.init,E=D.info,x=D.loader_config,O=D),g.v6&&(E.jsAttributes={...E.jsAttributes,isWorker:!0}),(0,a.CX)(e,E),(0,a.Dg)(e,A||{}),(0,a.GE)(e,x||{}),(0,a.sU)(e,T),function(e,t,n){n||(0,f.R)(e,"api"),h(t);var m=u.ee.get(e),b=m.get("tracer"),y="api-",w=y+"ixn-";function A(){}(0,c.D)(["setErrorHandler","finished","addToTrace","inlineHit","addRelease"],(function(e,r){t[r]=x(y,r,!0,"api")})),t.addPageAction=x(y,"addPageAction",!0,o.D.pageAction),t.setCurrentRouteName=x(y,"routeName",!0,o.D.spa),t.setPageViewName=function(t,r){if("string"==typeof t)return"/"!==t.charAt(0)&&(t="/"+t),(0,a.OP)(e).customTransaction=(r||"https://web.archive.org/web/20230314214432/http://custom.transaction")+t,x(y,"setPageViewName",!0,"api")()},t.setCustomAttribute=function(t,r){const n=(0,a.C5)(e);return(0,a.CX)(e,{...n,jsAttributes:{...n.jsAttributes,[t]:r}}),x(y,"setCustomAttribute",!0,"api")()},t.interaction=function(){return(new A).get()};var E=A.prototype={createTracer:function(e,t){var r={},n=this,i="function"==typeof t;return(0,s.p)(w+"tracer",[(0,d.zO)(),e,r],n,o.D.spa,m),function(){if(b.emit((i?"":"no-")+"fn-start",[(0,d.zO)(),n,i],r),i)try{return t.apply(this,arguments)}catch(e){throw b.emit("fn-err",[arguments,this,"string"==typeof e?new Error(e):e],r),e}finally{b.emit("fn-end",[(0,d.zO)()],r)}}}};function x(e,t,r,n){return function(){return(0,s.p)(p.xS,["API/"+t+"/called"],void 0,o.D.metrics,m),(0,s.p)(e+t,[(0,d.zO)()].concat(i()(arguments)),r?null:this,n,m),r?void 0:this}}function T(){r.e(439).then(r.bind(r,5692)).then((t=>{let{setAPI:r}=t;r(e),(0,f.L)(e,"api")})).catch((()=>(0,v.Z)("Downloading runtime APIs failed...")))}(0,c.D)("actionText,setName,setAttribute,save,ignore,onEnd,getContext,end,get".split(","),(function(e,t){E[t]=x(w,t,void 0,o.D.spa)})),t.noticeError=function(e,t){"string"==typeof e&&(e=new Error(e)),(0,s.p)(p.xS,["API/noticeError/called"],void 0,o.D.metrics,m),(0,s.p)("err",[e,(0,d.zO)(),!1,t],void 0,o.D.jserrors,m)},g.v6?T():(0,l.b)((()=>T()),!0)}(e,O,w),(0,m.Qy)(e,D,"api"),(0,m.Qy)(e,_,"exposed"),(0,m.EZ)("activatedFeatures",y),(0,m.EZ)("setToken",(t=>function(e,t){var r=u.ee.get(t);e&&"object"==typeof e&&((0,c.D)(e,(function(e,t){if(!t)return(b[e]||[]).forEach((t=>{(0,s.p)("block-"+e,[],void 0,t,r)}));y[e]||((0,s.p)("feat-"+e,[],void 0,b[e],r),y[e]=!0)})),(0,f.L)(t,o.D.pageViewEvent))}(t,e))),O}},909:(e,t,r)=>{"use strict";r.d(t,{Z:()=>i,q:()=>o});var n=r(2325);function i(e){switch(e){case n.D.ajax:return[n.D.jserrors];case n.D.sessionTrace:return[n.D.ajax,n.D.pageViewEvent];case n.D.pageViewTiming:return[n.D.pageViewEvent];default:return[]}}function o(e){return e===n.D.jserrors?[]:["auto"]}},2325:(e,t,r)=>{"use strict";r.d(t,{D:()=>n,p:()=>i});const n={ajax:"ajax",jserrors:"jserrors",metrics:"metrics",pageAction:"page_action",pageViewEvent:"page_view_event",pageViewTiming:"page_view_timing",sessionTrace:"session_trace",spa:"spa"},i={[n.pageViewEvent]:1,[n.pageViewTiming]:2,[n.metrics]:3,[n.jserrors]:4,[n.ajax]:5,[n.sessionTrace]:6,[n.pageAction]:7,[n.spa]:8}},8683:e=>{e.exports=function(e,t,r){t||(t=0),void 0===r&&(r=e?e.length:0);for(var n=-1,i=r-t||0,o=Array(i<0?0:i);++n<i;)o[n]=e[t+n];return o}}},n={};function i(e){var t=n[e];if(void 0!==t)return t.exports;var o=n[e]={exports:{}};return r[e](o,o.exports,i),o.exports}i.m=r,i.n=e=>{var t=e&&e.__esModule?()=>e.default:()=>e;return i.d(t,{a:t}),t},i.d=(e,t)=>{for(var r in t)i.o(t,r)&&!i.o(e,r)&&Object.defineProperty(e,r,{enumerable:!0,get:t[r]})},i.f={},i.e=e=>Promise.all(Object.keys(i.f).reduce(((t,r)=>(i.f[r](e,t),t)),[])),i.u=e=>(({78:"page_action-aggregate",147:"metrics-aggregate",193:"session_trace-aggregate",317:"jserrors-aggregate",348:"page_view_timing-aggregate",439:"async-api",729:"lazy-loader",786:"page_view_event-aggregate",873:"spa-aggregate",898:"ajax-aggregate"}[e]||e)+"."+{78:"2f41aaf7",147:"28086cfb",178:"52056f28",193:"545db67a",317:"941c6e17",348:"a7d9d7be",439:"737e0ca6",729:"540ab0d1",786:"2ae3c96c",873:"494130b7",898:"52cc993d"}[e]+"-1227.min.js"),i.o=(e,t)=>Object.prototype.hasOwnProperty.call(e,t),e={},t="NRBA:",i.l=(r,n,o,a)=>{if(e[r])e[r].push(n);else{var s,c;if(void 0!==o)for(var u=document.getElementsByTagName("script"),d=0;d<u.length;d++){var f=u[d];if(f.getAttribute("src")==r||f.getAttribute("data-webpack")==t+o){s=f;break}}s||(c=!0,(s=document.createElement("script")).charset="utf-8",s.timeout=120,i.nc&&s.setAttribute("nonce",i.nc),s.setAttribute("data-webpack",t+o),s.src=r),e[r]=[n];var l=(t,n)=>{s.onerror=s.onload=null,clearTimeout(g);var i=e[r];if(delete e[r],s.parentNode&&s.parentNode.removeChild(s),i&&i.forEach((e=>e(n))),t)return t(n)},g=setTimeout(l.bind(null,void 0,{type:"timeout",target:s}),12e4);s.onerror=l.bind(null,s.onerror),s.onload=l.bind(null,s.onload),c&&document.head.appendChild(s)}},i.r=e=>{"undefined"!=typeof Symbol&&Symbol.toStringTag&&Object.defineProperty(e,Symbol.toStringTag,{value:"Module"}),Object.defineProperty(e,"__esModule",{value:!0})},i.p="https://web.archive.org/web/20230314214432/https://js-agent.newrelic.com/",(()=>{var e={703:0,946:0};i.f.j=(t,r)=>{var n=i.o(e,t)?e[t]:void 0;if(0!==n)if(n)r.push(n[2]);else{var o=new Promise(((r,i)=>n=e[t]=[r,i]));r.push(n[2]=o);var a=i.p+i.u(t),s=new Error;i.l(a,(r=>{if(i.o(e,t)&&(0!==(n=e[t])&&(e[t]=void 0),n)){var o=r&&("load"===r.type?"missing":r.type),a=r&&r.target&&r.target.src;s.message="Loading chunk "+t+" failed.\n("+o+": "+a+")",s.name="ChunkLoadError",s.type=o,s.request=a,n[1](s)}}),"chunk-"+t,t)}};var t=(t,r)=>{var n,o,[a,s,c]=r,u=0;if(a.some((t=>0!==e[t]))){for(n in s)i.o(s,n)&&(i.m[n]=s[n]);if(c)c(i)}for(t&&t(r);u<a.length;u++)o=a[u],i.o(e,o)&&e[o]&&e[o][0](),e[o]=0},r=window.webpackChunkNRBA=window.webpackChunkNRBA||[];r.forEach(t.bind(null,0)),r.push=t.bind(null,r.push.bind(r))})();var o={};(()=>{"use strict";i.r(o);var e=i(2325),t=i(6562);const r=Object.values(e.D);function n(e){const n={};return r.forEach((r=>{n[r]=function(e,r){return!1!==(0,t.Mt)(r,"".concat(e,".enabled"))}(r,e)})),n}var a=i(2384),s=i(909),c=i(9252),u=i(2053),d=i(8283),f=i(6625),l=i(4329),g=i(1509),v=i(2650),p=i(2374),h=i(8610);class m extends g.W{constructor(e,t,r){let n=!(arguments.length>3&&void 0!==arguments[3])||arguments[3];super(e,t,r),this.hasAggregator=!1,this.auto=n,this.abortHandler,n&&(0,l.R)(e,r)}importAggregator(){if(this.hasAggregator||!this.auto)return;this.hasAggregator=!0;const e=async()=>{try{const{lazyLoader:e}=await i.e(729).then(i.bind(i,8110)),{Aggregate:t}=await e(this.featureName,"aggregate");new t(this.agentIdentifier,this.aggregator)}catch(e){(0,h.Z)("Downloading ".concat(this.featureName," failed...")),this.abortHandler?.()}};p.v6?e():(0,v.b)((()=>e()),!0)}}var b,y,w,A=i(2484);class E extends m{constructor(e,t){let r=!(arguments.length>2&&void 0!==arguments[2])||arguments[2];super(e,t,A.t,r),(0,f.v)(e),(0,d.B)(e,"firstbyte",(0,u.yf)()),(0,v.K)((()=>this.measureDomContentLoaded())),(0,v.b)((()=>this.measureWindowLoaded()),!0),this.importAggregator()}measureWindowLoaded(){var t=(0,u.zO)();(0,d.B)(this.agentIdentifier,"onload",t+(0,u.os)()),(0,c.p)("timing",["load",t],void 0,e.D.pageViewTiming,this.ee)}measureDomContentLoaded(){(0,d.B)(this.agentIdentifier,"domContent",(0,u.zO)()+(0,u.os)())}}b=E,y="featureName",w=A.t,(y=function(e){var t=function(e,t){if("object"!=typeof e||null===e)return e;var r=e[Symbol.toPrimitive];if(void 0!==r){var n=r.call(e,t||"default");if("object"!=typeof n)return n;throw new TypeError("@@toPrimitive must return a primitive value.")}return("string"===t?String:Number)(e)}(e,"string");return"symbol"==typeof t?t:String(t)}(y))in b?Object.defineProperty(b,y,{value:w,enumerable:!0,configurable:!0,writable:!0}):b[y]=w;var x=i(9557),T=i(7022);class _ extends x.w{constructor(e){super(e),this.aggregatedData={}}store(e,t,r,n,i){var o=this.getBucket(e,t,r,i);return o.metrics=function(e,t){t||(t={count:0});return t.count+=1,(0,T.D)(e,(function(e,r){t[e]=D(r,t[e])})),t}(n,o.metrics),o}merge(e,t,r,n,i){var o=this.getBucket(e,t,n,i);if(o.metrics){var a=o.metrics;a.count+=r.count,(0,T.D)(r,(function(e,t){if("count"!==e){var n=a[e],i=r[e];i&&!i.c?a[e]=D(i.t,n):a[e]=function(e,t){if(!t)return e;t.c||(t=O(t.t));return t.min=Math.min(e.min,t.min),t.max=Math.max(e.max,t.max),t.t+=e.t,t.sos+=e.sos,t.c+=e.c,t}(i,a[e])}}))}else o.metrics=r}storeMetric(e,t,r,n){var i=this.getBucket(e,t,r);return i.stats=D(n,i.stats),i}getBucket(e,t,r,n){this.aggregatedData[e]||(this.aggregatedData[e]={});var i=this.aggregatedData[e][t];return i||(i=this.aggregatedData[e][t]={params:r||{}},n&&(i.custom=n)),i}get(e,t){return t?this.aggregatedData[e]&&this.aggregatedData[e][t]:this.aggregatedData[e]}take(e){for(var t={},r="",n=!1,i=0;i<e.length;i++)t[r=e[i]]=j(this.aggregatedData[r]),t[r].length&&(n=!0),delete this.aggregatedData[r];return n?t:null}}function D(e,t){return null==e?function(e){e?e.c++:e={c:1};return e}(t):t?(t.c||(t=O(t.t)),t.c+=1,t.t+=e,t.sos+=e*e,e>t.max&&(t.max=e),e<t.min&&(t.min=e),t):{t:e}}function O(e){return{t:e,min:e,max:e,sos:e*e,c:1}}function j(e){return"object"!=typeof e?[]:(0,T.D)(e,k)}function k(e,t){return t}var P=i(6797),S=i(5526);var I,C=i(6998),N=i(8544),R=i(6382),M=-1,L=function(e){addEventListener("pageshow",(function(t){t.persisted&&(M=t.timeStamp,e(t))}),!0)},B=function(){return window.performance&&performance.getEntriesByType&&performance.getEntriesByType("navigation")[0]},z=function(){var e=B();return e&&e.activationStart||0},V=function(e,t){var r=B(),n="navigate";return M>=0?n="back-forward-cache":r&&(n=document.prerendering||z()>0?"prerender":document.wasDiscarded?"restore":r.type.replace(/_/g,"-")),{name:e,value:void 0===t?-1:t,rating:"good",delta:0,entries:[],id:"v3-".concat(Date.now(),"-").concat(Math.floor(8999999999999*Math.random())+1e12),navigationType:n}},W=function(e,t,r){try{if(PerformanceObserver.supportedEntryTypes.includes(e)){var n=new PerformanceObserver((function(e){Promise.resolve().then((function(){t(e.getEntries())}))}));return n.observe(Object.assign({type:e,buffered:!0},r||{})),n}}catch(e){}},q=function(e,t){var r=function r(n){"pagehide"!==n.type&&"hidden"!==document.visibilityState||(e(n),t&&(removeEventListener("visibilitychange",r,!0),removeEventListener("pagehide",r,!0)))};addEventListener("visibilitychange",r,!0),addEventListener("pagehide",r,!0)},Z=function(e,t,r,n){var i,o;return function(a){t.value>=0&&(a||n)&&((o=t.value-(i||0))||void 0===i)&&(i=t.value,t.delta=o,t.rating=function(e,t){return e>t[1]?"poor":e>t[0]?"needs-improvement":"good"}(t.value,r),e(t))}},H=function(e){document.prerendering?addEventListener("prerenderingchange",(function(){return e()}),!0):e()},F=(new Date,0),U=1/0,G=0,X=function(e){e.forEach((function(e){e.interactionId&&(U=Math.min(U,e.interactionId),G=Math.max(G,e.interactionId),F=G?(G-U)/7+1:0)}))},Q=function(){return I?F:performance.interactionCount||0},K=function(){"interactionCount"in performance||I||(I=W("event",X,{type:"event",buffered:!0,durationThreshold:0}))},Y=0,J=function(){return Q()-Y},$=[],ee={},te=function(e){var t=$[$.length-1],r=ee[e.interactionId];if(r||$.length<10||e.duration>t.latency){if(r)r.entries.push(e),r.latency=Math.max(r.latency,e.duration);else{var n={id:e.interactionId,latency:e.duration,entries:[e]};ee[n.id]=n,$.push(n)}$.sort((function(e,t){return t.latency-e.latency})),$.splice(10).forEach((function(e){delete ee[e.id]}))}},re=i(2545);class ne extends m{constructor(r,n){var i;let o=!(arguments.length>2&&void 0!==arguments[2])||arguments[2];if(super(r,n,R.t,o),i=this,p.il){if(this.pageHiddenTime=(0,C.e)(),this.performanceObserver,this.lcpPerformanceObserver,this.clsPerformanceObserver,this.fiRecorded=!1,"PerformanceObserver"in window&&"function"==typeof window.PerformanceObserver){this.performanceObserver=new PerformanceObserver((function(){return i.perfObserver(...arguments)}));try{this.performanceObserver.observe({entryTypes:["paint"]})}catch(e){}this.lcpPerformanceObserver=new PerformanceObserver((function(){return i.lcpObserver(...arguments)}));try{this.lcpPerformanceObserver.observe({entryTypes:["largest-contentful-paint"]})}catch(e){}this.clsPerformanceObserver=new PerformanceObserver((function(){return i.clsObserver(...arguments)}));try{this.clsPerformanceObserver.observe({type:"layout-shift",buffered:!0})}catch(e){}}this.fiRecorded=!1;["click","keydown","mousedown","pointerdown","touchstart"].forEach((e=>{(0,N.iz)(e,(function(){return i.captureInteraction(...arguments)}))})),function(e,t){t=t||{},H((function(){var r=[200,500];K();var n,i=V("INP"),o=function(e){e.forEach((function(e){e.interactionId&&te(e),"first-input"===e.entryType&&!$.some((function(t){return t.entries.some((function(t){return e.duration===t.duration&&e.startTime===t.startTime}))}))&&te(e)}));var t,r=(t=Math.min($.length-1,Math.floor(J()/50)),$[t]);r&&r.latency!==i.value&&(i.value=r.latency,i.entries=r.entries,n())},a=W("event",o,{durationThreshold:t.durationThreshold||40});n=Z(e,i,r,t.reportAllChanges),a&&(a.observe({type:"first-input",buffered:!0}),q((function(){o(a.takeRecords()),i.value<0&&J()>0&&(i.value=0,i.entries=[]),n(!0)})),L((function(){$=[],Y=Q(),i=V("INP"),n=Z(e,i,r,t.reportAllChanges)})))}))}((t=>{let{name:r,value:n,id:i}=t;(0,c.p)("timing",[r.toLowerCase(),n,{metricId:i}],void 0,e.D.pageViewTiming,this.ee)})),!0===(0,t.Mt)(this.agentIdentifier,"page_view_timing.long_task")&&(e=>{const t=t=>{t.forEach((t=>{const r={name:"LT",value:t.duration,info:{ltFrame:t.name,ltStart:t.startTime,ltCtr:t.attribution[0].containerType}};"window"!==r.info.ltCtr&&Object.assign(r.info,{ltCtrSrc:t.attribution[0].containerSrc,ltCtrId:t.attribution[0].containerId,ltCtrName:t.attribution[0].containerName}),e(r)}))};let r;try{PerformanceObserver.supportedEntryTypes.includes("longtask")&&(r=new PerformanceObserver((e=>{Promise.resolve().then((()=>{t(e.getEntries())}))})),r.observe({type:"longtask",buffered:!0}))}catch(e){}r&&(0,re.L)((()=>{t(r.takeRecords())}),!0)})((t=>{let{name:r,value:n,info:i}=t;(0,c.p)("timing",[r.toLowerCase(),n,i],void 0,e.D.pageViewTiming,this.ee)})),(0,C.N)((()=>{this.pageHiddenTime=(0,u.zO)(),(0,c.p)("docHidden",[this.pageHiddenTime],void 0,e.D.pageViewTiming,this.ee)}),!0),(0,N.bP)("pagehide",(()=>(0,c.p)("winPagehide",[(0,u.zO)()],void 0,e.D.pageViewTiming,this.ee))),this.importAggregator()}}perfObserver(t,r){t.getEntries().forEach((t=>{"first-paint"===t.name?(0,c.p)("timing",["fp",Math.floor(t.startTime)],void 0,e.D.pageViewTiming,this.ee):"first-contentful-paint"===t.name&&(0,c.p)("timing",["fcp",Math.floor(t.startTime)],void 0,e.D.pageViewTiming,this.ee)}))}lcpObserver(t,r){var n=t.getEntries();if(n.length>0){var i=n[n.length-1];if(this.pageHiddenTime<i.startTime)return;var o=[i],a=this.addConnectionAttributes({});a&&o.push(a),(0,c.p)("lcp",o,void 0,e.D.pageViewTiming,this.ee)}}clsObserver(t){t.getEntries().forEach((t=>{t.hadRecentInput||(0,c.p)("cls",[t],void 0,e.D.pageViewTiming,this.ee)}))}addConnectionAttributes(e){var t=navigator.connection||navigator.mozConnection||navigator.webkitConnection;if(t)return t.type&&(e["net-type"]=t.type),t.effectiveType&&(e["net-etype"]=t.effectiveType),t.rtt&&(e["net-rtt"]=t.rtt),t.downlink&&(e["net-dlink"]=t.downlink),e}captureInteraction(r){if(r instanceof t.Yu.EV&&!this.fiRecorded){var n=Math.round(r.timeStamp),i={type:r.type};this.addConnectionAttributes(i),n<=(0,u.zO)()?i.fid=(0,u.zO)()-n:n>(0,u.os)()&&n<=Date.now()?(n-=(0,u.os)(),i.fid=(0,u.zO)()-n):n=(0,u.zO)(),this.fiRecorded=!0,(0,c.p)("timing",["fi",n,i],void 0,e.D.pageViewTiming,this.ee)}}}!function(e,t,r){(t=function(e){var t=function(e,t){if("object"!=typeof e||null===e)return e;var r=e[Symbol.toPrimitive];if(void 0!==r){var n=r.call(e,t||"default");if("object"!=typeof n)return n;throw new TypeError("@@toPrimitive must return a primitive value.")}return("string"===t?String:Number)(e)}(e,"string");return"symbol"==typeof t?t:String(t)}(t))in e?Object.defineProperty(e,t,{value:r,enumerable:!0,configurable:!0,writable:!0}):e[t]=r}(ne,"featureName",R.t);const ie={dedicated:Boolean(p._A?.Worker),shared:Boolean(p._A?.SharedWorker),service:Boolean(p._A?.navigator?.serviceWorker)};let oe,ae,se;var ce=i(6034);class ue extends m{constructor(t,r){let n=!(arguments.length>2&&void 0!==arguments[2])||arguments[2];super(t,r,ce.t9,n),function(e){if(!oe){if(ie.dedicated){oe=Worker;try{p._A.Worker=r(oe,"Dedicated")}catch(e){o(e,"Dedicated")}if(ie.shared){ae=SharedWorker;try{p._A.SharedWorker=r(ae,"Shared")}catch(e){o(e,"Shared")}}else n("Shared");if(ie.service){se=navigator.serviceWorker.register;try{p._A.navigator.serviceWorker.register=(t=se,function(){for(var e=arguments.length,r=new Array(e),n=0;n<e;n++)r[n]=arguments[n];return i("Service",r[1]?.type),t.apply(navigator.serviceWorker,r)})}catch(e){o(e,"Service")}}else n("Service");var t;return}n("All")}function r(e,t){return"undefined"==typeof Proxy?e:new Proxy(e,{construct:(e,r)=>(i(t,r[1]?.type),new e(...r))})}function n(t){p.v6||e("Workers/".concat(t,"/Unavailable"))}function i(t,r){e("Workers/".concat(t,"module"===r?"/Module":"/Classic"))}function o(t,r){e("Workers/".concat(r,"/SM/Unsupported")),(0,h.Z)("NR Agent: Unable to capture ".concat(r," workers."),t)}}((t=>(0,c.p)(ce.xS,[t],void 0,e.D.metrics,this.ee))),this.importAggregator()}}!function(e,t,r){(t=function(e){var t=function(e,t){if("object"!=typeof e||null===e)return e;var r=e[Symbol.toPrimitive];if(void 0!==r){var n=r.call(e,t||"default");if("object"!=typeof n)return n;throw new TypeError("@@toPrimitive must return a primitive value.")}return("string"===t?String:Number)(e)}(e,"string");return"symbol"==typeof t?t:String(t)}(t))in e?Object.defineProperty(e,t,{value:r,enumerable:!0,configurable:!0,writable:!0}):e[t]=r}(ue,"featureName",ce.t9),new class{constructor(e){let t=arguments.length>1&&void 0!==arguments[1]?arguments[1]:(0,S.ky)(16);this.agentIdentifier=t,this.sharedAggregator=new _({agentIdentifier:this.agentIdentifier}),this.features={},this.desiredFeatures=new Set(e.features||[]),this.desiredFeatures.add(E),Object.assign(this,(0,a.j)(this.agentIdentifier,e,e.loaderType||"agent")),this.start()}get config(){return{info:(0,t.C5)(this.agentIdentifier),init:(0,t.P_)(this.agentIdentifier),loader_config:(0,t.DL)(this.agentIdentifier),runtime:(0,t.OP)(this.agentIdentifier)}}start(){const t="features";try{const r=n(this.agentIdentifier),i=Array.from(this.desiredFeatures);i.sort(((t,r)=>e.p[t.featureName]-e.p[r.featureName])),i.forEach((t=>{if(r[t.featureName]||t.featureName===e.D.pageViewEvent){const e=(0,s.Z)(t.featureName),n=e.every((e=>r[e]));n||(0,h.Z)("".concat(t.featureName," is enabled but one or more dependent features has been disabled (").concat(JSON.stringify(e),"). This may cause unintended consequences or missing data...")),this.features[t.featureName]=new t(this.agentIdentifier,this.sharedAggregator)}})),(0,P.Qy)(this.agentIdentifier,this.features,t)}catch(e){(0,h.Z)("Failed to initialize all enabled instrument classes (agent aborted) -",e);for(const e in this.features)this.features[e].abortHandler?.();const r=(0,P.fP)();return delete r.initializedAgents[this.agentIdentifier]?.api,delete r.initializedAgents[this.agentIdentifier]?.[t],delete this.sharedAggregator,r.ee?.abort(),delete r.ee?.get(this.agentIdentifier),!1}}}({features:[E,ne,ue],loaderType:"lite"})})(),window.NRBA=o})();</script> <noscript><style>form.antibot * :not(.antibot-message) { display: none !important; }</style> </noscript><script async src="https://web.archive.org/web/20230314214432js_/https://www.googletagmanager.com/gtag/js?id=UA-66610693-3"></script> <script>window.dataLayer = window.dataLayer || [];function gtag(){dataLayer.push(arguments)};gtag("js", new Date());gtag("set", "developer_id.dMDhkMT", true);gtag('set', {cookie_flags: 'SameSite=None;Secure'});gtag("config", "UA-66610693-3", {"groups":"default","anonymize_ip":true,"page_placeholder":"PLACEHOLDER_page_path","link_attribution":true,"allow_ad_personalization_signals":false,"custom_map":{"dimension2":"node_title","dimension3":"node_id","dimension7":"content_type"}});gtag("config", "G-HEQ0YF2VYL", {"groups":"default","page_placeholder":"PLACEHOLDER_page_location","link_attribution":true,"allow_ad_personalization_signals":false});gtag("config", "UA-33523145-1", {"groups":"default","anonymize_ip":true,"page_placeholder":"PLACEHOLDER_page_path","link_attribution":true,"allow_ad_personalization_signals":false,"custom_map":{"dimension2":"node_title","dimension3":"node_id","dimension7":"content_type"}});gtag("event", "custom", {"node_title":"Standard Reference Data","node_id":"419156","content_type":"Laboratory\/Organizational Unit"});</script> <link rel="canonical" href="https://web.archive.org/web/20230314214432/https://www.nist.gov/srd"/> <link rel="shortlink" href="https://web.archive.org/web/20230314214432/https://www.nist.gov/node/419156"/> <meta name="description" content="For over 50 years, NIST has developed and distributed Standard Reference Data in Chemistry, Engineering, Fluids and Condensed Phases, Material Sciences, Mathematical and Computer Sciences and Physics.."/> <meta name="dcterms.title" content="Standard Reference Data"/> <meta name="dcterms.description" content="For over 50 years, NIST has developed and distributed Standard Reference Data in Chemistry, Engineering, Fluids and Condensed Phases, Material Sciences, Mathematical and Computer Sciences and Physics.."/> <meta name="dcterms.date" content="2012-12-12T11:04-05:00"/> <meta name="dcterms.type" content="text"/> <meta name="dcterms.format" content="text/html"/> <meta name="dcterms.identifier" content="https://www.nist.gov/srd"/> <meta name="dcterms.source" content="NIST"/> <meta name="dcterms.created" content="2012-12-12T11:04-05:00"/> <meta name="dcterms.modified" content="2022-06-14T16:23-04:00"/> <meta name="citation_title" content="Standard Reference Data | NIST"/> <meta property="og:site_name" content="NIST"/> <meta property="og:type" content="Article"/> <meta property="og:url" content="https://web.archive.org/web/20230314214432/https://www.nist.gov/srd"/> <meta property="og:title" content="Standard Reference Data"/> <meta property="og:description" content="For over 50 years, NIST has developed and distributed Standard Reference Data in Chemistry, Engineering, Fluids and Condensed Phases, Material Sciences, Mathematical and Computer Sciences and Physics.."/> <meta property="article:published_time" content="2012-12-12T11:04-05:00"/> <meta property="article:modified_time" content="2022-06-14T16:23-04:00"/> <meta name="google-site-verification" content="QMu0ODkER3rN5hLcMLqNVf7e3bkjYsNLTuhqfH48jCA"/> <meta name="twitter:card" content="summary_large_image"/> <meta name="twitter:site" content="NIST"/> <meta name="twitter:description" content="For over 50 years, NIST has developed and distributed Standard Reference Data in Chemistry, Engineering, Fluids and Condensed Phases, Material Sciences, Mathematical and Computer Sciences and Physics.."/> <meta name="twitter:title" content="Standard Reference Data"/> <meta name="twitter:url" content="https://web.archive.org/web/20230314214432im_/https://www.nist.gov/srd"/> <meta name="Generator" content="Drupal 9 (https://www.drupal.org)"/> <meta name="MobileOptimized" content="width"/> <meta name="HandheldFriendly" content="true"/> <meta name="viewport" content="width=device-width, initial-scale=1.0"/> <meta name="nist_search_modified" class="elastic" content="2022-06-14T16:23:00-04:00"/> <script type="application/ld+json">{ "@context": "https://web.archive.org/web/20230314214432/https://schema.org", "@graph": [ { "@type": "Article", "headline": "Standard Reference Data | NIST", "description": "\u003Cp\u003EFor over 50 years, NIST has developed and distributed Standard Reference Data in Chemistry, Engineering, Fluids and Condensed Phases, Material Sciences, Mathematical and Computer Sciences and Physics..\u003C/p\u003E", "image": { "@type": "ImageObject", "representativeOfPage": "True" }, "datePublished": "2012-12-12T11:04-05:00", "dateModified": "2022-06-14T16:23-04:00" } ] }</script> <meta name="nist_search_bundle" class="elastic" content="laboratory_organizational_unit"/> <link rel="icon" href="/web/20230314214432im_/https://www.nist.gov/themes/custom/nist_www/favicon.ico" type="image/vnd.microsoft.icon"/> <title>Standard Reference Data | NIST</title> <link rel="stylesheet" media="all" href="/web/20230314214432cs_/https://www.nist.gov/sites/default/files/css/css_GoWW7n3uRaUcun4S2-erRAYRkLmHlzlCTf9N7Gw3xRI.css"/> <link rel="stylesheet" media="screen" href="/web/20230314214432cs_/https://www.nist.gov/sites/default/files/css/css_gD8QmGaNfUQuThtjB-S0EwEOZZNJP1QfUU1bDdLHbMU.css"/> <link rel="stylesheet" media="print" href="/web/20230314214432cs_/https://www.nist.gov/sites/default/files/css/css_zbjDhj-AmeVwgu9y0DlPwEfp7l-a5BpoK3MpoGmRB6o.css"/> <link rel="stylesheet" media="all" href="/web/20230314214432cs_/https://www.nist.gov/sites/default/files/css/css_PV0KmreUx3hVeYI6yGypf71UDz9BSQl1Z5DjiESDh-Y.css"/> <link rel="stylesheet" media="screen" href="/web/20230314214432cs_/https://www.nist.gov/sites/default/files/css/css_dXhP8gFSR5hd16LUS1TrwJ15l9WTOxqff1l1a5ojF4o.css"/> <script src="/web/20230314214432js_/https://www.nist.gov/sites/default/files/js/js_VDwaIMNiRtzQn-NZvj1F9loIzJ-i4yEDiruzS8Z6Ejo.js"></script> </head> <body class="node-419156"> <a href="#main-content" class="visually-hidden focusable" data-elastic-exclude> Skip to main content </a> <div class="dialog-off-canvas-main-canvas" data-off-canvas-main-canvas>  <section data-elastic-exclude class="usa-banner" aria-label="Official government website"> <div class="usa-accordion"> <header class="usa-banner__header"> <div class="usa-banner__inner"> <div class="grid-col-auto"> <img class="usa-banner__header-flag" src="/web/20230314214432im_/https://www.nist.gov/libraries/nist-component-library/dist/img/us_flag_small.png" alt="U.S. flag"> </div> <div class="grid-col-fill tablet:grid-col-auto"> <p class="usa-banner__header-text">An official website of the United States government</p> <p class="usa-banner__header-action" aria-hidden="true">Here鈥檚 how you know</p> </div> <button class="usa-accordion__button usa-banner__button" aria-expanded="false" aria-controls="gov-banner-default"> <span class="usa-banner__button-text">Here鈥檚 how you know</span> </button> </div> </header> <div class="usa-banner__content usa-accordion__content" id="gov-banner-default"> <div class="grid-row grid-gap-lg"> <div class="usa-banner__guidance tablet:grid-col-6"> <img class="usa-banner__icon usa-media-block__img" src="/web/20230314214432im_/https://www.nist.gov/libraries/nist-component-library/dist/img/icon-dot-gov.svg" role="img" alt="" aria-hidden="true"> <div class="usa-media-block__body"> <p> <strong>Official websites use .gov</strong> <br/> A <strong>.gov</strong> website belongs to an official government organization in the United States. </p> </div> </div> <div class="usa-banner__guidance tablet:grid-col-6"> <img class="usa-banner__icon usa-media-block__img" src="/web/20230314214432im_/https://www.nist.gov/libraries/nist-component-library/dist/img/icon-https.svg" role="img" alt="" aria-hidden="true"> <div class="usa-media-block__body"> <p> <strong>Secure .gov websites use HTTPS</strong> <br/> A <strong>lock</strong> ( <span class="icon-lock"> <svg xmlns="http://www.w3.org/2000/svg" width="52" height="64" viewbox="0 0 52 64" class="usa-banner__lock-image" role="img" aria-labelledby="banner-lock-title banner-lock-description" focusable="false"> <title id="banner-lock-title">Lock</title> <desc id="banner-lock-description">A locked padlock</desc><path fill="#000000" fill-rule="evenodd" d="M26 0c10.493 0 19 8.507 19 19v9h3a4 4 0 0 1 4 4v28a4 4 0 0 1-4 4H4a4 4 0 0 1-4-4V32a4 4 0 0 1 4-4h3v-9C7 8.507 15.507 0 26 0zm0 8c-5.979 0-10.843 4.77-10.996 10.712L15 19v9h22v-9c0-6.075-4.925-11-11-11z"/></svg> </span> ) or <strong>https://</strong> means you鈥檝e safely connected to the .gov website. Share sensitive information only on official, secure websites. </p> </div> </div> </div> </div> </div> </section>  <div data-elastic-exclude>  <div class="nist-print-header" style="display:none;"> <p class="nist-print-header__url">https://www.nist.gov/srd</p> <img class="nist-print-header__logo" width="289" height="38" src="/web/20230314214432im_/https://www.nist.gov/libraries/nist-component-library/dist/img/logo/nist_logo_sidestack.svg" alt="National Institute of Standards and Technology"/> </div> <div class="usa-overlay"></div> <header class="usa-header nist-header--www nist-header--minimal" role="banner"> <div class="usa-navbar"> <div class="usa-logo flex-fill"> <a href="/web/20230314214432/https://www.nist.gov/" title="National Institute of Standards and Technology" aria-label="Home"> <img src="/web/20230314214432im_/https://www.nist.gov/libraries/nist-component-library/dist/img/logo/logo.svg" alt="National Institute of Standards and Technology" width="300px" height="80px"/> </a> </div> <div class="usa-header__right grid-row flex-auto"> <div class="grid-col-fill nist-header__search-group"> <form class="usa-search usa-search--small" accept-charset="UTF-8" action="/web/20230314214432/https://www.nist.gov/search" id="search_form" method="get"> <div role="search"> <label class="usa-sr-only" for="search-form">Search NIST</label> <input class="usa-input" id="search-form" type="search" name="s" placeholder="Search NIST" required="" maxlength="128"> <button class="usa-button" type="submit"><img src="/web/20230314214432im_/https://www.nist.gov/libraries/nist-component-library/dist/img/usa-icons-bg/search--white.svg" class="usa-search__submit-icon" alt="Search"></button> </div> </form> </div> <div class="grid-col-auto padding-left-1"> <button class="usa-menu-btn">Menu</button> </div> </div> </div> <nav aria-label="Primary navigation" class="usa-nav"> <div class="usa-nav__inner"> <button class="usa-nav__close">Close</button> <ul class="usa-nav__primary usa-accordion"> <li class="usa-nav__primary-item"> <button class="usa-accordion__button usa-nav__link" aria-expanded="false" aria-controls="primary_menu-1"><span>Topics</span></button> <div id="primary_menu-1" class="usa-nav__submenu usa-megamenu"> <div class="grid-row"> <div class="tablet:grid-col-fill"><ul class="usa-nav__submenu-list"> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/topics" class="usa-nav__link">All Topics</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/advanced-communications" class="usa-nav__link">Advanced communications</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/artificial-intelligence" class="usa-nav__link">Artificial intelligence</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/bioscience" class="usa-nav__link">Bioscience</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/buildings-construction" class="usa-nav__link">Buildings and construction</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/chemistry" class="usa-nav__link">Chemistry</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/climate" class="usa-nav__link">Climate</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/cybersecurity" class="usa-nav__link">Cybersecurity</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/electronics" class="usa-nav__link">Electronics</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/energy" class="usa-nav__link">Energy</a> </li> </ul></div><div class="column-break tablet:grid-col-fill"><ul class="usa-nav__submenu-list"> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/environment" class="usa-nav__link">Environment</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/fire" class="usa-nav__link">Fire</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/forensic-science" class="usa-nav__link">Forensic science</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/health" class="usa-nav__link">Health</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/information-technology" class="usa-nav__link">Information technology</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/infrastructure" class="usa-nav__link">Infrastructure</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/manufacturing" class="usa-nav__link">Manufacturing</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/materials" class="usa-nav__link">Materials</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/mathematics-statistics" class="usa-nav__link">Mathematics and statistics</a> </li> </ul></div><div class="column-break tablet:grid-col-fill"><ul class="usa-nav__submenu-list"> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/metrology" class="usa-nav__link">Metrology</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/nanotechnology" class="usa-nav__link">Nanotechnology</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/neutron-research" class="usa-nav__link">Neutron research</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/performance-excellence" class="usa-nav__link">Performance excellence</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/physics" class="usa-nav__link">Physics</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/public-safety" class="usa-nav__link">Public safety</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/resilience" class="usa-nav__link">Resilience</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/standards" class="usa-nav__link">Standards</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/transportation" class="usa-nav__link">Transportation</a> </li> </ul> </div> </div> </div> </li> <li class="usa-nav__primary-item"> <a class="usa-nav__link" href="/web/20230314214432/https://www.nist.gov/publications">Publications</a> </li> <li class="usa-nav__primary-item"> <button class="usa-accordion__button usa-nav__link" aria-expanded="false" aria-controls="primary_menu-3"><span>Labs & Major Programs</span></button> <div id="primary_menu-3" class="usa-nav__submenu usa-megamenu"> <div class="grid-row"> <div class="tablet:grid-col-fill"><ul class="usa-nav__submenu-list"> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/labs-major-programs/laboratories" class="usa-nav__link">Laboratories</a> <ul class="usa-nav__submenu-list"> <li> <a href="/web/20230314214432/https://www.nist.gov/ctl" class="usa-nav__link">Communications Technology Laboratory</a> </li> <li> <a href="/web/20230314214432/https://www.nist.gov/el" class="usa-nav__link">Engineering Laboratory</a> </li> <li> <a href="/web/20230314214432/https://www.nist.gov/itl" class="usa-nav__link">Information Technology Laboratory</a> </li> <li> <a href="/web/20230314214432/https://www.nist.gov/mml" class="usa-nav__link">Material Measurement Laboratory</a> </li> <li> <a href="/web/20230314214432/https://www.nist.gov/pml" class="usa-nav__link">Physical Measurement Laboratory</a> </li> </ul> </li> </ul></div><div class="column-break tablet:grid-col-fill"><ul class="usa-nav__submenu-list"> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/labs-major-programs/user-facilities" class="usa-nav__link">User Facilities</a> <ul class="usa-nav__submenu-list"> <li> <a href="/web/20230314214432/https://www.nist.gov/ncnr" class="usa-nav__link">NIST Center for Neutron Research</a> </li> <li> <a href="/web/20230314214432/https://www.nist.gov/cnst" class="usa-nav__link">CNST NanoFab</a> </li> </ul> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/labs-major-programs/research-test-beds" class="usa-nav__link">Research Test Beds</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/laboratories/projects-programs" class="usa-nav__link">Research Projects</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/laboratories/tools-instruments" class="usa-nav__link">Tools & Instruments</a> </li> </ul></div><div class="column-break tablet:grid-col-fill"><ul class="usa-nav__submenu-list"> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/labs-major-programs/major-programs" class="usa-nav__link">Major Programs</a> <ul class="usa-nav__submenu-list"> <li> <a href="/web/20230314214432/https://www.nist.gov/baldrige" class="usa-nav__link">Baldrige Performance Excellence Program</a> </li> <li> <a href="/web/20230314214432/https://www.nist.gov/chips" class="usa-nav__link">CHIPS for America Initiative</a> </li> <li> <a href="/web/20230314214432/https://www.nist.gov/mep" class="usa-nav__link">Manufacturing Extension Partnership (MEP)</a> </li> <li> <a href="/web/20230314214432/https://www.nist.gov/oam" class="usa-nav__link">Office of Advanced Manufacturing</a> </li> <li> <a href="/web/20230314214432/https://www.nist.gov/spo" class="usa-nav__link">Special Programs Office</a> </li> <li> <a href="/web/20230314214432/https://www.nist.gov/tpo" class="usa-nav__link">Technology Partnerships Office</a> </li> </ul> </li> </ul> </div> </div> </div> </li> <li class="usa-nav__primary-item"> <button class="usa-accordion__button usa-nav__link usa-current" aria-expanded="false" aria-controls="primary_menu-4"><span>Services & Resources</span></button> <div id="primary_menu-4" class="usa-nav__submenu usa-megamenu"> <div class="grid-row"> <div class="tablet:grid-col-fill"><ul class="usa-nav__submenu-list"> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/services-resources/standards-and-measurements" class="usa-nav__link">Standards and Measurements</a> <ul class="usa-nav__submenu-list"> <li> <a href="/web/20230314214432/https://www.nist.gov/calibrations" class="usa-nav__link">Calibration Services</a> </li> <li> <a href="/web/20230314214432/https://www.nist.gov/nvlap" class="usa-nav__link">Laboratory Accreditation (NVLAP)</a> </li> <li> <a href="/web/20230314214432/https://www.nist.gov/nist-quality-system" class="usa-nav__link">Quality System</a> </li> <li> <a href="/web/20230314214432/https://www.nist.gov/srm" class="usa-nav__link">Standard Reference Materials (SRMs)</a> </li> <li> <a href="/web/20230314214432/https://www.nist.gov/standardsgov" class="usa-nav__link">Standards.gov</a> </li> <li> <a href="/web/20230314214432/https://www.nist.gov/pml/time-and-frequency-division/time-services" class="usa-nav__link">Time Services</a> </li> <li> <a href="/web/20230314214432/https://www.nist.gov/pml/owm" class="usa-nav__link">Office of Weights and Measures</a> </li> </ul> </li> </ul></div><div class="column-break tablet:grid-col-fill"><ul class="usa-nav__submenu-list"> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/services-resources/software" class="usa-nav__link">Software</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/data" class="usa-nav__link usa-current">Data</a> <ul class="usa-nav__submenu-list"> <li> <a href="https://web.archive.org/web/20230314214432/https://webbook.nist.gov/chemistry/" class="usa-nav__link">Chemistry WebBook</a> </li> <li> <a href="https://web.archive.org/web/20230314214432/https://nvd.nist.gov/" class="usa-nav__link">National Vulnerability Database</a> </li> <li> <a href="/web/20230314214432/https://www.nist.gov/pml/productsservices/physical-reference-data" class="usa-nav__link">Physical Reference Data</a> </li> <li> <a href="/web/20230314214432/https://www.nist.gov/srd" class="usa-nav__link usa-current">Standard Reference Data (SRD)</a> </li> </ul> </li> <li class="usa-nav__submenu-item"> <a href="https://web.archive.org/web/20230314214432/https://www.nist.gov/shop" class="usa-nav__link">Storefront</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/tpo" class="usa-nav__link">License & Patents</a> </li> </ul></div><div class="column-break tablet:grid-col-fill"><ul class="usa-nav__submenu-list"> <li class="usa-nav__submenu-item"> <a href="https://web.archive.org/web/20230314214432/https://csrc.nist.gov/" class="usa-nav__link">Computer Security Resource Center (CSRC)</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/nist-research-library" class="usa-nav__link">NIST Research Library</a> </li> </ul> </div> </div> </div> </li> <li class="usa-nav__primary-item"> <button class="usa-accordion__button usa-nav__link" aria-expanded="false" aria-controls="primary_menu-5"><span>News & Events</span></button> <div id="primary_menu-5" class="usa-nav__submenu usa-megamenu"> <div class="grid-row"> <div class="tablet:grid-col-fill"><ul class="usa-nav__submenu-list"> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/news-events/news" class="usa-nav__link">News</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/news-events/events" class="usa-nav__link">Events</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/blogs" class="usa-nav__link">Blogs</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/feature-stories" class="usa-nav__link">Feature Stories</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/awards" class="usa-nav__link">Awards</a> </li> </ul></div><div class="column-break tablet:grid-col-fill"><ul class="usa-nav__submenu-list"> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/video-gallery" class="usa-nav__link">Video Gallery</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/image-gallery" class="usa-nav__link">Image Gallery</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/director/pao/media-contacts" class="usa-nav__link">Media Contacts</a> </li> </ul> </div> </div> </div> </li> <li class="usa-nav__primary-item"> <button class="usa-accordion__button usa-nav__link" aria-expanded="false" aria-controls="primary_menu-6"><span>About NIST</span></button> <div id="primary_menu-6" class="usa-nav__submenu usa-megamenu"> <div class="grid-row"> <div class="tablet:grid-col-fill"><ul class="usa-nav__submenu-list"> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/about-nist" class="usa-nav__link">About Us</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/about-nist/contact-us" class="usa-nav__link">Contact Us</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/about-nist/visit" class="usa-nav__link">Visit</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/careers" class="usa-nav__link">Careers</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/director/nist-organization-structure" class="usa-nav__link">Our Organization</a> <ul class="usa-nav__submenu-list"> <li> <a href="/web/20230314214432/https://www.nist.gov/director" class="usa-nav__link">Office of the Director</a> </li> <li> <a href="/web/20230314214432/https://www.nist.gov/director/nist-organization-structure/budget-planning" class="usa-nav__link">Budget & Planning</a> </li> </ul> </li> </ul></div><div class="column-break tablet:grid-col-fill"><ul class="usa-nav__submenu-list"> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/about-nist/work-nist" class="usa-nav__link">Work with NIST</a> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/history" class="usa-nav__link">History</a> <ul class="usa-nav__submenu-list"> <li> <a href="https://web.archive.org/web/20230314214432/http://nistdigitalarchives.contentdm.oclc.org/" class="usa-nav__link">NIST Digital Archives</a> </li> <li> <a href="/web/20230314214432/https://www.nist.gov/nist-museum" class="usa-nav__link">NIST Museum</a> </li> <li> <a href="/web/20230314214432/https://www.nist.gov/nist-and-nobel" class="usa-nav__link">NIST and the Nobel</a> </li> </ul> </li> <li class="usa-nav__submenu-item"> <a href="/web/20230314214432/https://www.nist.gov/education" class="usa-nav__link">Educational Resources</a> </li> </ul> </div> </div> </div> </li> </ul> </div> </nav> </header>  </div> <div class="grid-container"> <div data-drupal-messages-fallback class="hidden"></div> </div> <div id="block-nist-www-content" class="nist-block"> <section class="nist-page__content usa-section clearfix"> <a id="main-content" tabindex="-1"></a> <div class="nist-section-header nist-section-header--menu"> <div class="nist-section-header__main grid-container"> <div class="grid-row"> <div class="nist-section-header__title tablet-lg:grid-col-4"> <h1 class="nist-page__title">Standard Reference Data</h1> </div> <div class="nist-section-header__desc tablet-lg:grid-col-8"> <div class="text-with-summary"> <p>For over 50 years, NIST has developed and distributed Standard Reference Data in Chemistry, Engineering, Fluids and Condensed Phases, Material Sciences, Mathematical and Computer Sciences and Physics..</p> </div> </div> </div> </div> </div> <div class="grid-container margin-top-4"> <div class="grid-row grid-gap-6"> <aside class="nist-page__region nist-page__region--sidebar-first tablet-lg:grid-col-4 desktop-lg:grid-col-3"> <div>  <div data-elastic-exclude="" class="nist-block"> <nav> <ul class="usa-sidenav usa-accordion "> <li class="usa-sidenav__item usa-sidenav__item--parent"> <a href="/web/20230314214432/https://www.nist.gov/srd/shop" data-drupal-link-system-path="">SHOP</a> <button class="usa-accordion__button" aria-expanded="false" aria-controls="menu-standard-reference-data-1"><span class="usa-sr-only">Expand or Collapse</span></button> <ul id="menu-standard-reference-data-1" class="usa-sidenav__sublist usa-accordion"> <li class="usa-sidenav__item"> <a href="/web/20230314214432/https://www.nist.gov/srd/shop/srd-online-subscriptions" data-drupal-link-system-path="">SRD Online Subscriptions</a> </li> <li class="usa-sidenav__item"> <a href="/web/20230314214432/https://www.nist.gov/srd/shop/special-database-catalog" data-drupal-link-system-path="">Special Database Catalog</a> </li> </ul> </li> <li class="usa-sidenav__item"> <a href="/web/20230314214432/https://www.nist.gov/srd/srd-catalog" data-drupal-link-system-path="">SRD Catalog</a> </li> <li class="usa-sidenav__item"> <a href="/web/20230314214432/https://www.nist.gov/srd/free-srd" data-drupal-link-system-path="">Free SRD</a> </li> <li class="usa-sidenav__item"> <a href="/web/20230314214432/https://www.nist.gov/srd/srd-sorted-topic" data-drupal-link-system-path="">SRD Sorted by Topic</a> </li> <li class="usa-sidenav__item"> <a href="/web/20230314214432/https://www.nist.gov/srd/public-law" data-drupal-link-system-path="">Public Law</a> </li> <li class="usa-sidenav__item"> <a href="/web/20230314214432/https://www.nist.gov/srd/srd-definition" data-drupal-link-system-path="">SRD Definition</a> </li> <li class="usa-sidenav__item"> <a href="/web/20230314214432/https://www.nist.gov/srd/critical-evaluation-criteria" data-drupal-link-system-path="">Critical Evaluation Criteria</a> </li> <li class="usa-sidenav__item"> <a href="/web/20230314214432/https://www.nist.gov/srd/journal-physical-and-chemical-reference-data" data-drupal-link-system-path="">Journal of Physical and Chemical Reference Data</a> </li> <li class="usa-sidenav__item"> <a href="/web/20230314214432/https://www.nist.gov/srd/national-standard-reference-data-series" data-drupal-link-system-path="">National Standard Reference Data Series</a> </li> <li class="usa-sidenav__item usa-sidenav__item--parent"> <a href="/web/20230314214432/https://www.nist.gov/srd/related-data-products-and-links" data-drupal-link-system-path="">Related Data Products and Links</a> <button class="usa-accordion__button" aria-expanded="false" aria-controls="menu-standard-reference-data-10"><span class="usa-sr-only">Expand or Collapse</span></button> <ul id="menu-standard-reference-data-10" class="usa-sidenav__sublist usa-accordion"> <li class="usa-sidenav__item"> <a href="/web/20230314214432/https://www.nist.gov/srd/related-data-products-and-links/curated-data-collections" data-drupal-link-system-path="">Curated Data Collections</a> </li> <li class="usa-sidenav__item"> <a href="/web/20230314214432/https://www.nist.gov/srd/related-data-products-and-links/special-databases-and-special-software" data-drupal-link-system-path="">Special Databases and Special Software</a> </li> <li class="usa-sidenav__item"> <a href="/web/20230314214432/https://www.nist.gov/srd/related-data-products-and-links/nist-public-data" data-drupal-link-system-path="">NIST Public Data</a> </li> <li class="usa-sidenav__item"> <a href="/web/20230314214432/https://www.nist.gov/srd/related-data-products-and-links/international-metrology-resource-registry" data-drupal-link-system-path="">International Metrology Resource Registry</a> </li> </ul> </li> </ul> </nav> </div>  </div> </aside> <div class="nist-page__region nist-page__region--content tablet-lg:grid-col-8 desktop-lg:grid-col-9"> <div class="nist-block"> <div class="paragraph paragraph--type--hero paragraph--view-mode--default"> <div class="nist-hero grid-row grid-gap-2"> <div class="nist-hero__item tablet:grid-col-4 "> <div class="nist-hero__item-inner"> <div class="nist-hero__image"> <a href="https://web.archive.org/web/20230314214432/https://www.nist.gov/srd/nist-standard-reference-database-1a-v17"> <picture> <source srcset="/web/20230314214432im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2018/07/10/mass_spec_cd_scan.webp?itok=9K9gxnK8 1x, /web/20230314214432im_/https://www.nist.gov/sites/default/files/styles/1200w_x_720h/public/images/2018/07/10/mass_spec_cd_scan.webp?itok=OLz_yJjr 2x" media="(min-width: 480px)" type="image/webp" width="600" height="360"/> <source srcset="/web/20230314214432im_/https://www.nist.gov/sites/default/files/styles/300w_x_180h/public/images/2018/07/10/mass_spec_cd_scan.webp?itok=S0Mbdkhz 1x, /web/20230314214432im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2018/07/10/mass_spec_cd_scan.webp?itok=9K9gxnK8 2x" media="(min-width: 0px)" type="image/webp" width="300" height="180"/> <source srcset="/web/20230314214432im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2018/07/10/mass_spec_cd_scan.jpg?itok=9K9gxnK8 1x, /web/20230314214432im_/https://www.nist.gov/sites/default/files/styles/1200w_x_720h/public/images/2018/07/10/mass_spec_cd_scan.jpg?itok=OLz_yJjr 2x" media="(min-width: 480px)" type="image/jpeg" width="600" height="360"/> <source srcset="/web/20230314214432im_/https://www.nist.gov/sites/default/files/styles/300w_x_180h/public/images/2018/07/10/mass_spec_cd_scan.jpg?itok=S0Mbdkhz 1x, /web/20230314214432im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2018/07/10/mass_spec_cd_scan.jpg?itok=9K9gxnK8 2x" media="(min-width: 0px)" type="image/jpeg" width="300" height="180"/> <img loading="eager" src="/web/20230314214432im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2018/07/10/mass_spec_cd_scan.jpg?itok=9K9gxnK8" width="600" height="360" alt="Mass Spec " title="Mass Spec: NIST/EPA/NIH Mass Spectral Library" typeof="foaf:Image"/> </picture> </a> </div> <div class="nist-hero__caption"> <a href="https://web.archive.org/web/20230314214432/https://www.nist.gov/srd/nist-standard-reference-database-1a-v17"> <div class="text">Mass Spec: NIST/EPA/NIH Mass Spectral Library</div> </a> </div> </div> </div> <div class="nist-hero__item tablet:grid-col-4 "> <div class="nist-hero__item-inner"> <div class="nist-hero__image"> <a href="https://web.archive.org/web/20230314214432/https://www.nist.gov/srd/nist-standard-reference-database-3"> <picture> <source srcset="/web/20230314214432im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2019/11/20/lattice_135x135.webp?itok=Ub6E29S3 1x, /web/20230314214432im_/https://www.nist.gov/sites/default/files/styles/1200w_x_720h/public/images/2019/11/20/lattice_135x135.webp?itok=psT6pwwZ 2x" media="(min-width: 480px)" type="image/webp" width="600" height="360"/> <source srcset="/web/20230314214432im_/https://www.nist.gov/sites/default/files/styles/300w_x_180h/public/images/2019/11/20/lattice_135x135.webp?itok=6luDRwpR 1x, /web/20230314214432im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2019/11/20/lattice_135x135.webp?itok=Ub6E29S3 2x" media="(min-width: 0px)" type="image/webp" width="300" height="180"/> <source srcset="/web/20230314214432im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2019/11/20/lattice_135x135.jpg?itok=Ub6E29S3 1x, /web/20230314214432im_/https://www.nist.gov/sites/default/files/styles/1200w_x_720h/public/images/2019/11/20/lattice_135x135.jpg?itok=psT6pwwZ 2x" media="(min-width: 480px)" type="image/jpeg" width="600" height="360"/> <source srcset="/web/20230314214432im_/https://www.nist.gov/sites/default/files/styles/300w_x_180h/public/images/2019/11/20/lattice_135x135.jpg?itok=6luDRwpR 1x, /web/20230314214432im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2019/11/20/lattice_135x135.jpg?itok=Ub6E29S3 2x" media="(min-width: 0px)" type="image/jpeg" width="300" height="180"/> <img loading="eager" src="/web/20230314214432im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2019/11/20/lattice_135x135.jpg?itok=Ub6E29S3" width="600" height="360" alt="lattice" title="lattice" typeof="foaf:Image"/> </picture> </a> </div> <div class="nist-hero__caption"> <a href="https://web.archive.org/web/20230314214432/https://www.nist.gov/srd/nist-standard-reference-database-3"> <div class="text">NIST INORGANIC CRYSTAL STRUCTURE DATABASE (ICSD) SRD3</div> </a> </div> </div> </div> <div class="nist-hero__item tablet:grid-col-4 "> <div class="nist-hero__item-inner"> <div class="nist-hero__image"> <a href="/web/20230314214432/https://www.nist.gov/srd/refprop"> <picture> <source srcset="/web/20230314214432im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/srd/refprop2012_5.gif?itok=TvAWHKak 1x, /web/20230314214432im_/https://www.nist.gov/sites/default/files/styles/1200w_x_720h/public/images/srd/refprop2012_5.gif?itok=3tUcPtss 2x" media="(min-width: 480px)" type="image/webp" width="600" height="360"/> <source srcset="/web/20230314214432im_/https://www.nist.gov/sites/default/files/styles/300w_x_180h/public/images/srd/refprop2012_5.gif?itok=eooEsFC2 1x, /web/20230314214432im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/srd/refprop2012_5.gif?itok=TvAWHKak 2x" media="(min-width: 0px)" type="image/webp" width="300" height="180"/> <source srcset="/web/20230314214432im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/srd/refprop2012_5.gif?itok=TvAWHKak 1x, /web/20230314214432im_/https://www.nist.gov/sites/default/files/styles/1200w_x_720h/public/images/srd/refprop2012_5.gif?itok=3tUcPtss 2x" media="(min-width: 480px)" type="image/gif" width="600" height="360"/> <source srcset="/web/20230314214432im_/https://www.nist.gov/sites/default/files/styles/300w_x_180h/public/images/srd/refprop2012_5.gif?itok=eooEsFC2 1x, /web/20230314214432im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/srd/refprop2012_5.gif?itok=TvAWHKak 2x" media="(min-width: 0px)" type="image/gif" width="300" height="180"/> <img loading="eager" src="/web/20230314214432im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/srd/refprop2012_5.gif?itok=TvAWHKak" width="600" height="360" alt="refprop2012" typeof="foaf:Image"/> </picture> </a> </div> <div class="nist-hero__caption"> <a href="/web/20230314214432/https://www.nist.gov/srd/refprop"> <div class="text">REFPROP: NIST Reference Fluid Thermodynamic and Transport Properties</div> </a> </div> </div> </div> </div> </div> <div class="nist-content-row nist-content-row--width-legible paragraph paragraph--type--text paragraph--view-mode--default"> <div class="nist-block text-long"><div class="nist-callout"> <h2>New Database</h2> <p>Crystal Structure Database, for more information visit聽<a href="https://web.archive.org/web/20230314214432/https://icsd.nist.gov/">https://icsd.nist.gov</a></p> </div> <p>NIST produces the Nation鈥檚 Standard Reference Data (SRD). These data are assessed by experts and are trustworthy such that people can use the data with confidence and base significant decisions on the data. NIST provides 49 free SRD databases and 41 fee-based SRD databases. SRD must be compliant with rigorous critical evaluation criteria.聽Send questions to <span class="spamspan"><span class="u">data</span> [at] <span class="d">nist.gov</span></span> or call 1(844) 374-0183聽(Toll聽Free).</p></div> </div> <div class="nist-content-row nist-content-row--width-legible paragraph paragraph--type--text paragraph--view-mode--default"> <div class="nist-block text-long"><h2 class="nist-block__title">Popular Data Products</h2> <p><strong>Recent Update.聽</strong> NIST ICSD SRD3 is currently available, visit聽<a href="https://web.archive.org/web/20230314214432/https://icsd.nist.gov/">https://icsd.nist.gov</a></p> <ul><li><a href="https://web.archive.org/web/20230314214432/https://www.nist.gov/srd/refprop">REFPROP</a>: Reference Fluid Thermodynamic and Transport Properties <em><a href="https://web.archive.org/web/20230314214432/https://pages.nist.gov/REFPROP-docs/">FAQ</a></em></li> <li><a href="https://web.archive.org/web/20230314214432/https://www.nist.gov/srd/nist-standard-reference-database-1a">Mass Spec</a>: NIST/EPA/NIH Mass Spectral Library <a href="https://web.archive.org/web/20230314214432/https://chemdata.nist.gov/dokuwiki/doku.php?id=start">MS Data Center</a></li> <li><a href="https://web.archive.org/web/20230314214432/https://www.nist.gov/srd/nist-standard-reference-database-3">ICSD</a>:聽The NIST Inorganic Crystal Structure Database (ICSD) is聽a comprehensive collection of crystal structure data of inorganic compounds containing more than 210,000 entries and covering the literature from 1913.</li> <li><a href="https://web.archive.org/web/20230314214432/https://trc.nist.gov/tde.html">TDE</a>: NIST ThermoDataEngine聽</li> <li><a href="https://web.archive.org/web/20230314214432/https://www.nist.gov/srd/nist-special-database-33">PIV Cards</a>: NIST Test Personal Identity Verification Card</li> <li><a href="https://web.archive.org/web/20230314214432/https://www.nist.gov/srd/nist-standard-reference-database-31">PED</a>: NIST-ACers Phase Equilibria Diagram Database <a href="https://web.archive.org/web/20230314214432/https://s3.amazonaws.com/nist-srd/srd31_demo5.0.zip">5.0 demo</a>聽and <a href="https://web.archive.org/web/20230314214432/https://pages.nist.gov/PEDEditor/">PED Editor</a></li> <li> <p><a href="https://web.archive.org/web/20230314214432/https://www.nist.gov/srd/nist-standard-reference-database-100">SESSA</a>: NIST Simulation of Electron Spectra for Surface Analysis.聽<span><span><span><strong><span><span><span><span>Now Free!</span></span></span></span></strong></span></span></span></p> </li> <li><a href="/web/20230314214432/https://www.nist.gov/srd/srd-catalog/special-databases">Special Databases</a> - <a href="https://web.archive.org/web/20230314214432/https://www.nist.gov/topics/biometrics">Biometrics</a></li> <li><a href="https://web.archive.org/web/20230314214432/https://www.nist.gov/srd/nist-recommended-practice-guide">Selected NIST-Recommended Practice Guides in Material Sciences</a></li> </ul><p>Download <a href="https://web.archive.org/web/20230314214432/https://www.nist.gov/srd/nist-standard-reference-database-100">NIST Simulation of Electron Spectra for Surface Analysis</a>聽<strong>at no cost</strong>.聽聽The <a href="https://web.archive.org/web/20230314214432/https://www.nist.gov/srd/surface-data">surface databases</a> provide data for surface analysis by Auger-electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). In addition, the NIST Electron Elastic-Scattering Cross-Section Database (SRD 64) and the NIST Database of Cross Sections for Inner-Shell Ionization by Electron or Positron Impact (SRD 164) provide data for Monte Carlo simulations of electron transport in matter and for applications in atomic physics, plasma physics, radiation physics, and materials analysis by electron-probe microanalysis.</p> <h3>SRD Customer Support</h3> <p>100 Bureau Drive, Stop 6410<br> Gaithersburg, MD 20899-6410<br> Tel: 1(844) 374-0183聽(Toll聽Free)<br> e-mail <span class="spamspan"><span class="u">data</span> [at] <span class="d">nist.gov</span></span></p></div> </div> </div> </div> </div> </div> <div class="grid-row"> <div class="nist-resource-block nist-resource-block--first tablet:grid-col"> <div class="nist-resource-block__title-bar"> <div class="nist-resource-block__title"> <div class="nist-resource-block__icon"> <img aria-hidden="true" role="img" alt="decorative icon" src="/web/20230314214432im_/https://www.nist.gov/themes/custom/nist_www/img/resource-icons/link-icon-2x.png"/> </div> <h2> <div class="string">Data Portals</div> </h2> </div> </div> <div class="nist-resource-block__content"> <div class="nist-block"> <div class="text-long"><p><a class="CS_LinkBar_Item" data-entity-substitution="canonical" data-entity-type="node" data-entity-uuid="926f4ca6-7252-419c-967c-48f118824259" href="/web/20230314214432/https://www.nist.gov/srd/nist-standard-reference-database-1a" title="NIST Standard Reference Database 1A">Mass Spectrometry Data Center</a></p> <p><a class="CS_LinkBar_Item" href="/web/20230314214432/https://www.nist.gov/pml/data/index">Physical Reference Data Portal</a></p> <p><a class="CS_LinkBar_Item" href="https://web.archive.org/web/20230314214432/https://webbook.nist.gov/chemistry/">Chemistry WebBook</a></p> <p><a class="CS_LinkBar_Item" href="/web/20230314214432/https://www.nist.gov/pml/data/atomspec">Atomic Spectroscopy Databases</a></p> <p><a class="CS_LinkBar_Item" href="/web/20230314214432/https://www.nist.gov/mml/acmd/trc/index">Thermodynamics Research Center</a></p> <p><a class="CS_LinkBar_Item" href="/web/20230314214432/https://www.nist.gov/srm/index">Standard Reference Materials庐</a></p> <p><a class="CS_LinkBar_Item" href="https://web.archive.org/web/20230314214432/https://www.nist.gov/calibrations">Calibration Services</a></p> <p><a class="CS_LinkBar_Item" href="https://web.archive.org/web/20230314214432/https://www.nist.gov/services-resources/software">NIST Software</a></p> <p><a class="CS_LinkBar_Item" href="https://web.archive.org/web/20230314214432/https://www.github.com/usnistgov">NIST on GitHub</a></p></div> </div> </div> </div> <div class="nist-resource-block nist-resource-block--second nist-resource-block--green tablet:grid-col"> <div class="nist-resource-block__title-bar"> <div class="nist-resource-block__title"> <div class="nist-resource-block__icon"> <img aria-hidden="true" role="img" alt="decorative icon" src="/web/20230314214432im_/https://www.nist.gov/themes/custom/nist_www/img/resource-icons/link-icon-2x.png"/> </div> <h2> <div class="string">Popular Links</div> </h2> </div> </div> <div class="nist-resource-block__content"> <div class="nist-block"> <div class="text-long"><p><a class="CS_LinkBar_Item" href="/web/20230314214432/https://www.nist.gov/srm/exhibit">Exhibits at Upcoming Conferences</a></p> <p><a class="CS_LinkBar_Item" href="https://web.archive.org/web/20230314214432/https://www.nist.gov/mml/odi">Office of Data and Informatics</a></p> <p><a class="CS_LinkBar_Item" href="https://web.archive.org/web/20230314214432/https://www.nist.gov/mml">Material Measurement Laboratory</a></p> <p><a class="CS_LinkBar_Item" href="https://web.archive.org/web/20230314214432/https://www.nist.gov/pml">Physical Measurement Laboratory</a></p></div> </div> </div> </div> </div> <div class="grid-container"> </div> </section> </div> <div data-elastic-exclude>  <footer class="nist-footer padding-bottom-4"> <div class="grid-container nist-footer__info"> <div class="grid-row"> <div class="tablet:grid-col-6"> <div class="nist-footer__logo"> <a href="/web/20230314214432/https://www.nist.gov/" title="National Institute of Standards and Technology" rel="home"> <img class="nist-footer__logo-img" src="/web/20230314214432im_/https://www.nist.gov/libraries/nist-component-library/dist/img/logo/NIST-Logo-Brand-White.svg" alt="National Institute of Standards and Technology logo" width="300px" height="42px"/> </a> </div> <div class="nist-footer__contact"> <h3 class="nist-footer__contact-heading">HEADQUARTERS</h3> <address> 100 Bureau Drive<br> Gaithersburg, MD 20899<br> <a href="https://web.archive.org/web/20230314214432/tel:301-975-2000">301-975-2000</a> </address> <p> <a href="https://web.archive.org/web/20230314214432/mailto:do-webmaster@nist.gov">Webmaster</a> | <a href="https://web.archive.org/web/20230314214432/https://www.nist.gov/about-nist/contact-us">Contact Us</a> | <a href="https://web.archive.org/web/20230314214432/https://www.nist.gov/visit">Our Other Offices</a> </p> </div> </div> <div class="tablet:grid-col-6"> <div class="nist-footer__social-links"> <a class="nist-social nist-social--twitter-white" href="https://web.archive.org/web/20230314214432/https://twitter.com/NIST"> <span>Twitter</span> </a> <a class="nist-social nist-social--facebook-white" href="https://web.archive.org/web/20230314214432/https://www.facebook.com/NIST"> <span>Facebook</span> </a> <a class="nist-social nist-social--linkedin-white" href="https://web.archive.org/web/20230314214432/https://www.linkedin.com/company/nist"> <span>LinkedIn</span> </a> <a class="nist-social nist-social--instagram-white" href="https://web.archive.org/web/20230314214432/https://www.instagram.com/nist/"> <span>Instagram</span> </a> <a class="nist-social nist-social--youtube-white" href="https://web.archive.org/web/20230314214432/https://www.youtube.com/NIST"> <span>YouTube</span> </a> <a class="nist-social nist-social--giphy-white" href="https://web.archive.org/web/20230314214432/https://giphy.com/nist"> <span>Giphy</span> </a> <a class="nist-social nist-social--rss-white" href="https://web.archive.org/web/20230314214432/https://www.nist.gov/news-events/nist-rss-feeds"> <span>RSS Feed</span> </a> <a class="nist-social nist-social--envelope-white" href="https://web.archive.org/web/20230314214432/https://public.govdelivery.com/accounts/USNIST/subscriber/new"> <span>Mailing List</span> </a> </div> <div class="nist-footer__feedback"> How are we doing? <a class="usa-button" rel="nofollow" href="/web/20230314214432/https://www.nist.gov/form/nist-gov-feedback?destination=/srd" title="Provide feedback">Feedback</a> </div> </div> </div> </div> <div class="grid-container"> <div class="nist-footer__nav" role="navigation"> <ul> <li class="nist-footer__menu-item"> <a href="https://web.archive.org/web/20230314214432/https://www.nist.gov/privacy-policy">Site Privacy</a> </li> <li class="nist-footer__menu-item"> <a href="https://web.archive.org/web/20230314214432/https://www.nist.gov/oism/accessibility">Accessibility</a> </li> <li class="nist-footer__menu-item"> <a href="https://web.archive.org/web/20230314214432/https://www.nist.gov/privacy">Privacy Program</a> </li> <li class="nist-footer__menu-item"> <a href="https://web.archive.org/web/20230314214432/https://www.nist.gov/oism/copyrights">Copyrights</a> </li> <li class="nist-footer__menu-item"> <a href="https://web.archive.org/web/20230314214432/https://www.commerce.gov/vulnerability-disclosure-policy">Vulnerability Disclosure</a> </li> <li class="nist-footer__menu-item"> <a href="https://web.archive.org/web/20230314214432/https://www.nist.gov/no-fear-act-policy">No Fear Act Policy</a> </li> <li class="nist-footer__menu-item"> <a href="https://web.archive.org/web/20230314214432/https://www.nist.gov/office-director/freedom-information-act">FOIA</a> </li> <li class="nist-footer__menu-item"> <a href="https://web.archive.org/web/20230314214432/https://www.nist.gov/environmental-policy-statement">Environmental Policy</a> </li> <li class="nist-footer__menu-item"> <a href="https://web.archive.org/web/20230314214432/https://www.nist.gov/summary-report-scientific-integrity">Scientific Integrity</a> </li> <li class="nist-footer__menu-item"> <a href="https://web.archive.org/web/20230314214432/https://www.nist.gov/nist-information-quality-standards">Information Quality Standards</a> </li> <li class="nist-footer__menu-item"> <a href="https://web.archive.org/web/20230314214432/https://www.commerce.gov/">Commerce.gov</a> </li> <li class="nist-footer__menu-item"> <a href="https://web.archive.org/web/20230314214432/http://www.science.gov/">Science.gov</a> </li> <li class="nist-footer__menu-item"> <a href="https://web.archive.org/web/20230314214432/http://www.usa.gov/">USA.gov</a> </li> <li class="nist-footer__menu-item"> <a href="https://web.archive.org/web/20230314214432/https://vote.gov/">Vote.gov</a> </li> </ul> </div> </div> </footer>  </div> </div> <script type="application/json" data-drupal-selector="drupal-settings-json">{"path":{"baseUrl":"\/","scriptPath":null,"pathPrefix":"","currentPath":"node\/419156","currentPathIsAdmin":false,"isFront":false,"currentLanguage":"en"},"pluralDelimiter":"\u0003","suppressDeprecationErrors":true,"back_to_top":{"back_to_top_button_trigger":100,"back_to_top_prevent_on_mobile":false,"back_to_top_prevent_in_admin":true,"back_to_top_button_type":"image","back_to_top_button_text":"Back to top"},"google_analytics":{"account":"UA-66610693-3","trackOutbound":true,"trackMailto":true,"trackTel":true,"trackDownload":true,"trackDownloadExtensions":"7z|aac|arc|arj|asf|asx|avi|bin|bsh|c|csv|doc(x|m)?|dot(x|m)?|dw(fx|g|gd)|dxf|eps|epub|exe|f(90)|flv|gif|gz|gzip|hqx|jar|jpe?g|js|m1v|mp(2|3|4|e?g)|mobi|mov(ie)?|msi|msp|pdf|phps|pl|png|ppt(x|m)?|pot(x|m)?|pps(x|m)?|ppam|sld(x|m)?|thmx|qtm?|ra(m|r)?|rfa|rtf|rvt|sch|sea|sit|swf|tar|tgz|tif|txt|txz|wav|wma|wmv|wpd|wrl|xls(x|m|b)?|xlt(x|m)|xlam|xml|xsd|z|zip","trackDomainMode":1},"nist_search":{"clickTracking":"search-report-click","isDebug":false,"clickTrackEnabled":true,"message":"NIST Search in debug mode. Check the browsers network inspector for Click Track reporting results..."},"data":{"extlink":{"extTarget":false,"extTargetNoOverride":false,"extNofollow":false,"extNoreferrer":false,"extFollowNoOverride":false,"extClass":"ext","extLabel":"(link is external)","extImgClass":false,"extSubdomains":true,"extExclude":"\\.gov\\\/|\\.mil\\\/|\\manufacturingusa\\.com\\\/","extInclude":"","extCssExclude":"","extCssExplicit":"","extAlert":true,"extAlertText":"Thank you for visiting NIST. We hope your visit was informative. We have provided a link to this site because it has information that may be of interest to our users. NIST does not necessarily endorse the views expressed or the facts presented on this site. Further, NIST does not endorse any commercial products that may be advertised or available on this site. Click OK to be directed to your link.","mailtoClass":"0","mailtoLabel":"(link sends email)","extUseFontAwesome":false,"extIconPlacement":"append","extFaLinkClasses":"fa fa-external-link","extFaMailtoClasses":"fa fa-envelope-o","whitelistedDomains":[]}},"user":{"uid":0,"permissionsHash":"582eea317b4636ab5a0dffc8c6a006df3d6901ea5610498a0bbefc925ea1da0f"}}</script> <script src="/web/20230314214432js_/https://www.nist.gov/sites/default/files/js/js_AOg417qepduGFvXDI_SP863Nh3qVCuiSeO8_GAxUYnk.js"></script> <script src="https://web.archive.org/web/20230314214432js_/https://siteimproveanalytics.com/js/siteanalyze_6017546.js" async></script> <script src="/web/20230314214432js_/https://www.nist.gov/sites/default/files/js/js_fW_HPIBhPKScudp0ncbqzC9XffJ7ZsR1WI61FhqmFqg.js"></script> <script type="text/javascript">window.NREUM||(NREUM={});NREUM.info={"beacon":"gov-bam.nr-data.net","licenseKey":"37b7ccb661","applicationID":"1089704227","transactionName":"YFxUN0sADEdYVkBaClkWdwBNCA1aFkVVVABoWlcAUQQ=","queueTime":0,"applicationTime":105,"atts":"TBtXQQMaH0k=","errorBeacon":"gov-bam.nr-data.net","agent":""}</script></body> </html>

CINXE.COM

Standard Reference Data | NIST