The purification and preparation of high-purity PbCl2 and ternary alkali lead chloride single crystals

Abstract Purification and crystal growth of PbCl 2 and congruently melting ternary alkali lead chlorides, KPb 2 Cl 5 , RbPbCl 3 , RbPb 2 Cl 5 , and CsPbCl 3 , will be described in the present paper. Source materials were purified by the chlorination of molten chlorides with gaseous mixture of chlorinating agents in combination with a subsequent zone-melting. The efficiency of this method is confirmed by chemical analysis before and after purification and by the behaviour of the melts. Large single crystals of PbCl 2 , KPb 2 Cl 5 , RbPb 2 Cl 5 and CsPbCl 3 , 20 mm in diameter and 50–60 mm long, were grown by the Bridgman method. Their quality was checked by the optical absorption and elastic light scattering measurements.