Rn · radon

라돈

Takeaway

Recommended or revised twice between 1902 and 2024 (first record 1912, latest revision 1925).
It has no standard atomic weight today: a radioactive element without a characteristic terrestrial isotopic composition.

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
1912	222.4	no uncertainty	O=16	222.39166		10.1021/ja02224a601
1925	222	no uncertainty	O=16	221.991675		10.1039/CT9252700913

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