Ce · cerium

세륨

Takeaway

Recommended or revised 7 times between 1902 and 2024 (first record 1902, latest revision 1995).
Both revisions whose previous recommendation had an uncertainty kept the new value inside the previous (expanded) range.
The current standard atomic weight is 140.116(1) (recommended in 1995).

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	140	no uncertainty	O=16	139.99475		10.1007/BF01370337
1904	140.25	no uncertainty	O=16	140.24474062		10.1021/ja01991a001
1931	140.13	no uncertainty	O=16	140.12474512		10.1039/JR9310001617
1961	140.12	no uncertainty	12C=12	140.12		10.1021/ja00881a001
1969	140.12(1)	value(uncertainty)	12C=12	140.12		10.1351/pac197021010091
1985	140.115(4)	value(uncertainty)	12C=12	140.115	−0.500	10.1351/pac198658121677
1995	140.116(1)	value(uncertainty)	12C=12	140.116	0.250	10.1351/pac199668122339

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