relative molecular mass, \(M_{\text{r}}\)

https://doi.org/10.1351/goldbook.R05271
Ratio of the mass of a molecule to the @U06554@. Sometimes called the @M04000@ or @R05270@.
Sources:
Green Book, 2nd ed., p. 41 [Terms] [Book]
PAC, 1996, 68, 957. (Glossary of terms in quantities and units in Clinical Chemistry (IUPAC-IFCC Recommendations 1996)) on page 990 [Terms] [Paper]