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Atomic weight
Pr · praseodymium
프라세오디뮴
Takeaway
- Recommended or revised 9 times between 1902 and 2024 (first record 1902, latest revision 2017).
- All 4 revisions whose previous recommendation had an uncertainty kept the new value inside the previous (expanded) range.
- The current standard atomic weight is 140.907 66(1) (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 | 140.6 | no uncertainty | O=16 | 140.5947275 | 10.1007/BF01370337 | |
| 1916 | 140.9 | no uncertainty | O=16 | 140.89471625 | 10.1021/ja02176a001 | |
| 1925 | 140.92 | no uncertainty | O=16 | 140.9147155 | 10.1039/CT9252700913 | |
| 1961 | 140.907 | no uncertainty | 12C=12 | 140.907 | 10.1021/ja00881a001 | |
| 1969 | 140.9077(1) | value(uncertainty) | 12C=12 | 140.9077 | 10.1351/pac197021010091 | |
| 1985 | 140.907 65(3) | value(uncertainty) | 12C=12 | 140.90765 | −0.500 | 10.1351/pac198658121677 |
| 1995 | 140.907 65(2) | value(uncertainty) | 12C=12 | 140.90765 | 0.000 | 10.1351/pac199668122339 |
| 2013 | 140.907 66(2) | value(uncertainty) | 12C=12 | 140.90766 | 0.500 | 10.1515/pac-2015-0305 |
| 2017 | 140.907 66(1) | value(uncertainty) | 12C=12 | 140.90766 | 0.000 | 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