Dy · dysprosium

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Takeaway

Recommended or revised 7 times between 1902 and 2024 (first record 1908, latest revision 2001).
The one revision whose previous recommendation had an uncertainty kept the new value inside the previous (expanded) range.
The current standard atomic weight is 162.500(1) (recommended in 2001).

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
1908	162.5	no uncertainty	O=16	162.49390625		10.1021/ja01943a001
1925	162.52	no uncertainty	O=16	162.5139055		10.1039/CT9252700913
1931	162.46	no uncertainty	O=16	162.45390775		10.1039/JR9310001617
1955	162.51	no uncertainty	O=16	162.50390588		10.1021/ja01595a001
1961	162.50	no uncertainty	12C=12	162.5		10.1021/ja00881a001
1969	162.50(3)	value(uncertainty)	12C=12	162.5		10.1351/pac197021010091
2001	162.500(1)	value(uncertainty)	12C=12	162.5	0.000	10.1351/pac200375081107

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