Crystal growth of pure and impurity-doped lead chloride single crystals from the melt

Abstract

An account is given of the purification and the crystal growing of lead chloride. Difficulties observed are blackening of the material and the formation of oxides. It is evident that oxygen should be avoided. The influence of water vapour is studied with mass spectroscopy, crystal microbalance measurements, and microscopical observations.

Water vapour reacts with lead chloride giving lead (hydr)-oxychlorides and hydrochloric acid, but is not responsible for the blackening. On the surface of freshly cleaved crystals, which are exposed to water vapour rod-shaped hydrolysis products, are observed lying in the direction of the crystallographic a axis.

The blackening is not a thermal decomposition of lead chloride itself, but is attributed to organic contaminations.