β, βnuc, βlg

https://doi.org/10.1351/goldbook.08149
Parameter in a Brønsted relation expressing the sensitivity of the rate of deprotonation to basicity.
Note:
\(\beta_{\rm{nuc}}\) and \(\beta_{\lg}\) are used to correlate nucleophilic reactivity and leaving-group ability, respectively.
Source:
PAC, 2022, 94, 353. (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 2021)) on page 376 [Terms] [Paper]