Hf · hafnium

하프늄

Takeaway

Recommended or revised 6 times between 1902 and 2024 (first record 1931, latest revision 2019).
Both revisions whose previous recommendation had an uncertainty kept the new value inside the previous (expanded) range.
The current standard atomic weight is 178.486(6) (recommended in 2019).

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
1931	178.6	no uncertainty	O=16	178.5933025		10.1039/JR9310001617
1955	178.50	no uncertainty	O=16	178.49330625		10.1021/ja01595a001
1961	178.49	no uncertainty	12C=12	178.49		10.1021/ja00881a001
1969	178.49(3)	value(uncertainty)	12C=12	178.49		10.1351/pac197021010091
1985	178.49(2)	value(uncertainty)	12C=12	178.49	0.000	10.1351/pac198658121677
2019	178.486(6)	value(uncertainty)	12C=12	178.486	−0.200	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