https://doi.org/10.1351/goldbook.16253
Activity of a specified radionuclide (\(\ce{R}\)) in a material (\(\ce{M}\)) divided by amount of substance of that material.
Notes:
- The SI unit of molar activity is \(\pu{Bq mol-1}\), but molar activity is often expressed in unit \(\pu{Ci mmol-1}\). (Curie, symbol \(\pu{Ci}\), is a former unit of activity equal to exactly \(\pu{3.7E10 Bq}\).)
- If the term 'molar activity' is used without qualification, it should be made clear whether it refers to a material or a radionuclide. See: molar activity of a radionuclide.
Example: The certificate of analysis of adenosine 5′-triphosphate containing the isotopic label \(\ce{^{33}P}\) (called \(\ce{^{33}P}\)-gamma-ATP) quotes the activity as \(\pu{3000 Ci mmol-1}\). Using the recommended symbol, \(A_{m}(\ce{^{33}P},\ce{ATP}) = \pu{3000 Ci mmol-1}\).