Tm · thulium

툴륨

Takeaway

Recommended or revised 12 times between 1902 and 2024 (first record 1902, latest revision 2021).
All 5 revisions whose previous recommendation had an uncertainty kept the new value inside the previous (expanded) range.
The current standard atomic weight is 168.934 219(5) (recommended in 2021).

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	171	no uncertainty	O=16	170.9935875		10.1007/BF01370337
1909	168.5	no uncertainty	O=16	168.49368125		10.1021/ja01931a001
1922	169.9	no uncertainty	O=16	169.89362875		10.1021/ja01441a001
1925	169.4	no uncertainty	O=16	169.3936475		10.1039/CT9252700913
1953	168.94	no uncertainty	O=16	168.93366475		10.1039/JR9540004713
1961	168.934	no uncertainty	12C=12	168.934		10.1021/ja00881a001
1969	168.9342(1)	value(uncertainty)	12C=12	168.9342		10.1351/pac197021010091
1985	168.934 21(3)	value(uncertainty)	12C=12	168.93421	0.100	10.1351/pac198658121677
1995	168.934 21(2)	value(uncertainty)	12C=12	168.93421	0.000	10.1351/pac199668122339
2013	168.934 22(2)	value(uncertainty)	12C=12	168.93422	0.500	10.1515/pac-2015-0305
2017	168.934 218(6)	value(uncertainty)	12C=12	168.934218	−0.100	10.1515/pac-2019-0603
2021	168.934 219(5)	value(uncertainty)	12C=12	168.934219	0.167	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