point of zero charge (p.z.c.)

https://doi.org/10.1351/goldbook.P04704
A surface charge is at its point of zero charge when the @[email protected] is zero. It is a value of the negative logarithm of the activity in the bulk of the charge-determining ions.
Source:
PAC, 1991, 63, 895. (Nomenclature, symbols, definitions and measurements for electrified interfaces in aqueous dispersions of solids (Recommendations 1991)) on page 902 [Terms] [Paper]