C · carbon

탄소

Takeaway

Recommended or revised 11 times between 1902 and 2024 (first record 1902, latest revision 2009).
Of 2 revisions whose previous recommendation had an uncertainty, 1 (1969) put the new value outside the previous (expanded) range.
Since 2009, it has been given as the interval [12.0096, 12.0116] rather than a single value (the range found in normal materials).

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	12.00	no uncertainty	O=16	11.99955		10.1007/BF01370337
1916	12.005	no uncertainty	O=16	12.00454981		10.1021/ja02176a001
1925	12.000	no uncertainty	O=16	11.99955		10.1039/CT9252700913
1931	12.00	no uncertainty	O=16	11.99955		10.1039/JR9310001617
1937	12.01	no uncertainty	O=16	12.00954962		10.1039/JR9370001900
1938	12.010	no uncertainty	O=16	12.00954962		10.1039/JR9380001101
1953	12.011	no uncertainty	O=16	12.01054959		10.1039/JR9540004713
1961	12.011 15(5)	value(uncertainty)	12C=12	12.01115		10.1021/ja00881a001
1969	12.011(1)	value(uncertainty)	12C=12	12.011	−3.000	10.1351/pac197021010091
1995	12.0107(8)	value(uncertainty)	12C=12	12.0107	−0.300	10.1351/pac199668122339
2009	[12.0096, 12.0116]	interval	12C=12	12.0106 (interval midpoint, for calculation)		10.1351/PAC-REP-10-09-14

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