Na · sodium

소듐

Takeaway

Recommended or revised 10 times between 1902 and 2024 (first record 1902, latest revision 2005).
All 4 revisions whose previous recommendation had an uncertainty kept the new value inside the previous (expanded) range.
The current standard atomic weight is 22.989 769 28(2) (recommended in 2005).

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	23.05	no uncertainty	O=16	23.04913562		10.1007/BF01370337
1909	23.00	no uncertainty	O=16	22.9991375		10.1021/ja01931a001
1925	22.997	no uncertainty	O=16	22.99613761		10.1039/CT9252700913
1953	22.991	no uncertainty	O=16	22.99013784		10.1039/JR9540004713
1961	22.9898	no uncertainty	12C=12	22.9898		10.1021/ja00881a001
1969	22.9898(1)	value(uncertainty)	12C=12	22.9898		10.1351/pac197021010091
1971	22.989 77(1)	value(uncertainty)	12C=12	22.98977	−0.300	10.1351/pac197230030637
1985	22.989 768(6)	value(uncertainty)	12C=12	22.989768	−0.200	10.1351/pac198658121677
1995	22.989 770(2)	value(uncertainty)	12C=12	22.98977	0.333	10.1351/pac199668122339
2005	22.989 769 28(2)	value(uncertainty)	12C=12	22.98976928	−0.360	10.1351/pac200678112051

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