POINTS OF ZERO CHARGE OF INORGANIC PRECIPITATES

The points of zero charge of a number of slightly soluble salts of silver, calcium, barium, lead, and copper have been determined by means of the suspension effect technique. At their equivalent point silver salts and copper ferrocyanide were found to be negatively charged, whereas the other salts had a positive charge at this point. Our data are compared with data from the literature. Except for the silver halides, agreement between various authors is in general poor. A possible explanation is offered by assuming that exchange of ions on lattice defects" is responsible for the sign and magnitude of the point of zero charge. © 1969."