Ba · barium

바륨

Takeaway

Recommended or revised 7 times between 1902 and 2024 (first record 1902, latest revision 1985).
Both revisions whose previous recommendation had an uncertainty kept the new value inside the previous (expanded) range.
The current standard atomic weight is 137.327(7) (recommended in 1985).

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	137.4	no uncertainty	O=16	137.3948475		10.1007/BF01370337
1909	137.37	no uncertainty	O=16	137.36484862		10.1021/ja01931a001
1931	137.36	no uncertainty	O=16	137.354849		10.1039/JR9310001617
1961	137.34	no uncertainty	12C=12	137.34		10.1021/ja00881a001
1969	137.34(3)	value(uncertainty)	12C=12	137.34		10.1351/pac197021010091
1975	137.33(1)	value(uncertainty)	12C=12	137.33	−0.333	10.1351/pac197647010075
1985	137.327(7)	value(uncertainty)	12C=12	137.327	−0.300	10.1351/pac198658121677

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