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Atomic weight
Al · aluminium
알루미늄
Takeaway
- Recommended or revised 12 times between 1902 and 2024 (first record 1902, latest revision 2017).
- All 6 revisions whose previous recommendation had an uncertainty kept the new value inside the previous (expanded) range.
- The current standard atomic weight is 26.981 5384(3) (recommended in 2017).
| Yearyear of the recommendation | Value (as printed)as printed in CIAAW's table; digits in parentheses are the uncertainty (expanded range) in the last digits | Notationvalue(uncertainty), interval or no uncertainty | Scalebefore 1961 oxygen = 16, from 1961 ¹²C = 12 | Value, ¹²C scalepre-1961 values multiplied by 15.9994/16 | z vs previous(new − previous) ÷ previous uncertainty | ReportDOI of the CIAAW report |
|---|---|---|---|---|---|---|
| 1902 | 27.1 | no uncertainty | O=16 | 27.09898375 | 10.1007/BF01370337 | |
| 1922 | 27.0 | no uncertainty | O=16 | 26.9989875 | 10.1021/ja01441a001 | |
| 1925 | 26.97 | no uncertainty | O=16 | 26.96898862 | 10.1039/CT9252700913 | |
| 1951 | 26.98 | no uncertainty | O=16 | 26.97898825 | 10.1039/JR9530000001 | |
| 1961 | 26.9815 | no uncertainty | 12C=12 | 26.9815 | 10.1021/ja00881a001 | |
| 1969 | 26.9815(1) (corrected; source CSV 28.9815(1); see corrections file) | value(uncertainty) | 12C=12 | 26.9815 | 10.1351/pac197021010091 | |
| 1971 | 26.981 54(1) | value(uncertainty) | 12C=12 | 26.98154 | 0.400 | 10.1351/pac197230030637 |
| 1985 | 26.981 539(5) | value(uncertainty) | 12C=12 | 26.981539 | −0.100 | 10.1351/pac198658121677 |
| 1995 | 26.981 538(2) | value(uncertainty) | 12C=12 | 26.981538 | −0.200 | 10.1351/pac199668122339 |
| 2005 | 26.981 5386(8) | value(uncertainty) | 12C=12 | 26.9815386 | 0.300 | 10.1351/pac200678112051 |
| 2013 | 26.981 5385(7) | value(uncertainty) | 12C=12 | 26.9815385 | −0.125 | 10.1515/pac-2015-0305 |
| 2017 | 26.981 5384(3) | value(uncertainty) | 12C=12 | 26.9815384 | −0.143 | 10.1515/pac-2019-0603 |
Source: Standard atomic weights © IUPAC/CIAAW 2016–2024. Commission on Isotopic Abundances and Atomic Weights, Historical changes of standard atomic weights (compiled by J. Meija), https://www.ciaaw.org/historical-atomic-weights.htm