Be · beryllium

베릴륨

Takeaway

Recommended or revised 7 times between 1902 and 2024 (first record 1902, latest revision 2013).
Both revisions whose previous recommendation had an uncertainty kept the new value inside the previous (expanded) range.
The current standard atomic weight is 9.012 1831(5) (recommended in 2013).

Relative deviation from the current (or last) value, symmetric-log axis. Bars: uncertainty (expanded range); open circles: no uncertainty; orange boxes: intervals.

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	9.1	no uncertainty	O=16	9.09965875		10.1007/BF01370337
1925	9.02	no uncertainty	O=16	9.01966175		10.1039/CT9252700913
1949	9.013	no uncertainty	O=16	9.01266201		10.1039/JR9510000001
1961	9.0122	no uncertainty	12C=12	9.0122		10.1021/ja00881a001
1969	9.012 18(1)	value(uncertainty)	12C=12	9.01218		10.1351/pac197021010091
1985	9.012 182(3)	value(uncertainty)	12C=12	9.012182	0.200	10.1351/pac198658121677
2013	9.012 1831(5)	value(uncertainty)	12C=12	9.0121831	0.367	10.1515/pac-2015-0305

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