Isoelectric points of hydroxy double salts

Water-insoluble hydroxy double salts show pH-dependent surface-charging similar to that of metal oxides. While the pH-dependent surface-charging of metal oxides is very well-documented, the number of scientific papers reporting on the surface-charging of hydroxy double salts is limited. A collection of isoelectric points IEP of hydroxy double salts taken from the literature is presented. Electrokinetic behavior of paratacamite Cu 2 Cl(OH) 3 was studied experimentally, and its IEP was at pH about 8.5.