> **PROTOTYPE:** a suggestion, not an official CIAAW or IUPAC page. Official values are at [ciaaw.org](https://ciaaw.org).

# selenium

| Property | Value |
| --- | --- |
| Symbol | Se |
| Atomic number | 34 |
| IRI | `https://hendrikborgelt.github.io/Draft_for_IUPAC_CIAAW-Isotopic-Abundances-and-Atomic-Weights/elements/Selenium` |
| Wikidata | [Q876](https://www.wikidata.org/wiki/Q876) |

## Standard atomic weight

| Value | Year | Source | Status | Declaration |
| --- | --- | --- | --- | --- |
| 78.971(8) | 2013 | [10.1515/pac-2015-0305](https://doi.org/10.1515/pac-2015-0305) | Current | [`AW-Se-standard`](../id/AW-Se-standard.md) |
| 78.96(3) | 1969 | [10.1351/pac197021010091](https://doi.org/10.1351/pac197021010091) | Deprecated, see [`AW-Se-standard`](../id/AW-Se-standard.md) | [`AW-Se-standard-1969`](../id/AW-Se-standard-1969.md) |
| 78.96 | 1934 | [10.1039/JR9340000499](https://doi.org/10.1039/JR9340000499) | Deprecated, see [`AW-Se-standard-1969`](../id/AW-Se-standard-1969.md) | [`AW-Se-standard-1934`](../id/AW-Se-standard-1934.md) |
| 79.2 | 1903 | [10.1021/ja02003a001](https://doi.org/10.1021/ja02003a001) | Deprecated, see [`AW-Se-standard-1934`](../id/AW-Se-standard-1934.md) | [`AW-Se-standard-1903`](../id/AW-Se-standard-1903.md) |
| 79.1 | 1902 | [10.1007/BF01370337](https://doi.org/10.1007/BF01370337) | Deprecated, see [`AW-Se-standard-1903`](../id/AW-Se-standard-1903.md) | [`AW-Se-standard-1902`](../id/AW-Se-standard-1902.md) |

Notes: [r](#note-r)

## Isotopes

| A | Representative isotopic composition | Year | Source | Declaration | ChEBI | Wikidata |
| --- | --- | --- | --- | --- | --- | --- |
| [74](../id/Se-74.md) | 0.0086(3) | — | — | [`Abundance-Se74`](../id/Abundance-Se74.md) | — | [Q2806682](https://www.wikidata.org/wiki/Q2806682) |
| [76](../id/Se-76.md) | 0.0923(7) | — | — | [`Abundance-Se76`](../id/Abundance-Se76.md) | — | [Q2533598](https://www.wikidata.org/wiki/Q2533598) |
| [77](../id/Se-77.md) | 0.0760(7) | — | — | [`Abundance-Se77`](../id/Abundance-Se77.md) | — | [Q2433972](https://www.wikidata.org/wiki/Q2433972) |
| [78](../id/Se-78.md) | 0.2369(22) | — | — | [`Abundance-Se78`](../id/Abundance-Se78.md) | — | [Q1890759](https://www.wikidata.org/wiki/Q1890759) |
| [80](../id/Se-80.md) | 0.4980(36) | — | — | [`Abundance-Se80`](../id/Abundance-Se80.md) | — | [Q2387529](https://www.wikidata.org/wiki/Q2387529) |
| [82](../id/Se-82.md) | 0.0882(15) | — | — | [`Abundance-Se82`](../id/Abundance-Se82.md) | — | [Q2290353](https://www.wikidata.org/wiki/Q2290353) |

Notes: [r](#note-r)

## Notes

<a id="note-r"></a>**r** Range in isotopic composition of normal terrestrial material prevents a more precise standard atomic weight being given; the tabulated value and uncertainty should be applicable to normal material.

## Bibliography

<div class="csl-bib-body">
<div class="csl-entry">Atomic weights of the elements 1969. (1970). <i>Pure and Applied Chemistry</i>, <i>21</i>(1), 91–108. https://doi.org/10.1351/pac197021010091 <a href="https://doi.org/10.1351/pac197021010091">CrossRef</a> <a href="https://qlever.scholia.wiki/doi/10.1351/pac197021010091">Scholia</a></div>
<div class="csl-entry">Baxter, G. P., Curie, Mme. P., Lebeau, P., Hönigschmid, O., &#38; Meyer, R. J. (1934). Fourth Report of the Committee on Atomic Weights of the International Union of Chemistry. <i>J. Chem. Soc.</i>, <i>0</i>(0), 499–512. https://doi.org/10.1039/jr9340000499 <a href="https://doi.org/10.1039/JR9340000499">CrossRef</a> <a href="https://qlever.scholia.wiki/doi/10.1039/JR9340000499">Scholia</a></div>
<div class="csl-entry">Clarke, F. W. (1903). REPORT OF THE INTERNATIONAL COMMITTEE ON ATOMIC WEIGHTS. <i>Journal of the American Chemical Society</i>, <i>25</i>(1), 1–5. https://doi.org/10.1021/ja02003a001 <a href="https://doi.org/10.1021/ja02003a001">CrossRef</a> <a href="https://qlever.scholia.wiki/doi/10.1021/ja02003a001">Scholia</a></div>
<div class="csl-entry">Meija, J., Coplen, T. B., Berglund, M., Brand, W. A., De Bièvre, P., Gröning, M., Holden, N. E., Irrgeher, J., Loss, R. D., Walczyk, T., &#38; Prohaska, T. (2016). Atomic weights of the elements 2013 (IUPAC Technical Report). <i>Pure and Applied Chemistry</i>, <i>88</i>(3), 265–291. https://doi.org/10.1515/pac-2015-0305 <a href="https://doi.org/10.1515/pac-2015-0305">CrossRef</a> <a href="https://qlever.scholia.wiki/doi/10.1515/pac-2015-0305">Scholia</a></div>
<div class="csl-entry">Richards, Baxter, Hinrichsen, Köthner, P., &#38; Pellini, S. (1902). Zur Festsetzung der Atomgewichte. <i>Fresenius’ Zeitschrift für analytische Chemie</i>, <i>41</i>(2), 139–140. https://doi.org/10.1007/bf01370337 <a href="https://doi.org/10.1007/BF01370337">CrossRef</a> <a href="https://qlever.scholia.wiki/doi/10.1007/BF01370337">Scholia</a></div>
</div>

## Turtle

This resource as a file: [Selenium.ttl](Selenium.ttl)

```turtle
# Prototype: a suggestion, not an official CIAAW or IUPAC record. Official values are at https://ciaaw.org

@prefix adms: <http://www.w3.org/ns/adms#> .
@prefix chemrof: <https://w3id.org/chemrof/> .
@prefix ciaaw: <https://hendrikborgelt.github.io/Draft_for_IUPAC_CIAAW-Isotopic-Abundances-and-Atomic-Weights/ciaaw-draft#> .
@prefix ciaaw_draft: <https://hendrikborgelt.github.io/Draft_for_IUPAC_CIAAW-Isotopic-Abundances-and-Atomic-Weights/id/> .
@prefix dcterms: <http://purl.org/dc/terms/> .
@prefix element: <https://hendrikborgelt.github.io/Draft_for_IUPAC_CIAAW-Isotopic-Abundances-and-Atomic-Weights/elements/> .
@prefix owl: <http://www.w3.org/2002/07/owl#> .
@prefix qudt: <http://qudt.org/schema/qudt/> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix skos: <http://www.w3.org/2004/02/skos/core#> .
@prefix unit: <http://qudt.org/vocab/unit/> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .

ciaaw:note-r a ciaaw:Footnote ;
    skos:definition "Range in isotopic composition of normal terrestrial material prevents a more precise standard atomic weight being given; the tabulated value and uncertainty should be applicable to normal material."@en ;
    skos:notation "r" .

ciaaw_draft:AW-Se-standard-1902 a ciaaw:StandardAtomicWeightDeclaration ;
    dcterms:isReplacedBy ciaaw_draft:AW-Se-standard-1903 ;
    dcterms:issued "1902"^^xsd:gYear ;
    dcterms:source <https://doi.org/10.1007/BF01370337> ;
    owl:deprecated true ;
    adms:status <http://purl.org/adms/status/Deprecated> ;
    ciaaw:ofElement element:Selenium ;
    ciaaw:value [ a qudt:QuantityValue ;
            qudt:hasUnit unit:UNITLESS ;
            qudt:numericValue 79.1 ] .

ciaaw_draft:AW-Se-standard a ciaaw:StandardAtomicWeightDeclaration ;
    dcterms:issued "2013"^^xsd:gYear ;
    dcterms:replaces ciaaw_draft:AW-Se-standard-1969 ;
    dcterms:source <https://doi.org/10.1515/pac-2015-0305> ;
    ciaaw:footnote ciaaw:note-r ;
    ciaaw:ofElement element:Selenium ;
    ciaaw:value [ a qudt:QuantityValue ;
            qudt:hasUnit unit:UNITLESS ;
            qudt:numericValue 78.971 ;
            qudt:standardUncertainty 0.008 ;
            ciaaw:significantFigures 5 ;
            ciaaw:significantFiguresUncertainty 1 ] .

ciaaw_draft:AW-Se-standard-1903 a ciaaw:StandardAtomicWeightDeclaration ;
    dcterms:isReplacedBy ciaaw_draft:AW-Se-standard-1934 ;
    dcterms:issued "1903"^^xsd:gYear ;
    dcterms:replaces ciaaw_draft:AW-Se-standard-1902 ;
    dcterms:source <https://doi.org/10.1021/ja02003a001> ;
    owl:deprecated true ;
    adms:status <http://purl.org/adms/status/Deprecated> ;
    ciaaw:ofElement element:Selenium ;
    ciaaw:value [ a qudt:QuantityValue ;
            qudt:hasUnit unit:UNITLESS ;
            qudt:numericValue 79.2 ] .

ciaaw_draft:AW-Se-standard-1934 a ciaaw:StandardAtomicWeightDeclaration ;
    dcterms:isReplacedBy ciaaw_draft:AW-Se-standard-1969 ;
    dcterms:issued "1934"^^xsd:gYear ;
    dcterms:replaces ciaaw_draft:AW-Se-standard-1903 ;
    dcterms:source <https://doi.org/10.1039/JR9340000499> ;
    owl:deprecated true ;
    adms:status <http://purl.org/adms/status/Deprecated> ;
    ciaaw:ofElement element:Selenium ;
    ciaaw:value [ a qudt:QuantityValue ;
            qudt:hasUnit unit:UNITLESS ;
            qudt:numericValue 78.96 ] .

ciaaw_draft:AW-Se-standard-1969 a ciaaw:StandardAtomicWeightDeclaration ;
    dcterms:isReplacedBy ciaaw_draft:AW-Se-standard ;
    dcterms:issued "1969"^^xsd:gYear ;
    dcterms:replaces ciaaw_draft:AW-Se-standard-1934 ;
    dcterms:source <https://doi.org/10.1351/pac197021010091> ;
    owl:deprecated true ;
    adms:status <http://purl.org/adms/status/Deprecated> ;
    ciaaw:ofElement element:Selenium ;
    ciaaw:value [ a qudt:QuantityValue ;
            qudt:hasUnit unit:UNITLESS ;
            qudt:numericValue 78.96 ;
            qudt:standardUncertainty 0.03 ;
            ciaaw:significantFigures 4 ;
            ciaaw:significantFiguresUncertainty 1 ] .

element:Selenium a chemrof:ChemicalElement ;
    rdfs:label "selenium"@en ;
    ciaaw:currentStandardAtomicWeight ciaaw_draft:AW-Se-standard ;
    ciaaw:hasDeclaration ciaaw_draft:AW-Se-standard,
        ciaaw_draft:AW-Se-standard-1902,
        ciaaw_draft:AW-Se-standard-1903,
        ciaaw_draft:AW-Se-standard-1934,
        ciaaw_draft:AW-Se-standard-1969 ;
    ciaaw:hasIsotope ciaaw_draft:Se-74,
        ciaaw_draft:Se-76,
        ciaaw_draft:Se-77,
        ciaaw_draft:Se-78,
        ciaaw_draft:Se-80,
        ciaaw_draft:Se-82 ;
    ciaaw:standardAtomicWeightUncertainty 0.008 ;
    ciaaw:standardAtomicWeightValue 78.971 ;
    chemrof:atomic_number 34 ;
    chemrof:symbol "Se" .
```

[All atomic weights](../atomic-weights.md) · [All isotopic abundances](../isotopic-abundances.md)