Vapour growth and morphology of PbBr₂ crystals

Abstract

In this paper, the vapour transport of PbBr 2 under vacuum during vacuum distillation refining and its condensation on the wall of the vessel were described. The macro-and micro morphologies of PbBr 2 crystals grown in the vessel (glass tube) were studied. The crystal shape changed dramatically depending on the positions of condensation in the vessel, i.e., the crystal shape varied from an isometric polyhedron to columnar crystals with facets, and to a massive crystal without facets with a rise in the wall temperature. These results were interpreted in terms of the concentration gradient of the molecules in the vessel, surface roughening and/or surface melting of the crystals.