GROWTH OF ALPHA-PBF2 SINGLE-CRYSTALS FROM AQUEOUS-SOLUTIONS OF INORGANIC ACIDS

Growth of alpha-PbF2 crystals in 0.28M perchloric acid is described. The choice was based on an analysis of equilibria with the participation of fluoride ions and investigations of the solubility of lead fluoride in aqueous solutions. The enthalpy of dissolution of alpha-PbF2 in 0.28M perchloric acid is 1.6 kJ/mol, which is close to the value for pure water (2.4 kJ/mol). Orthorhombic lead fluoride single crystals were grown at spontaneous crystallization by a slow cooling method in the shape of plates (3x3x0.1 mm(3)) or prisms (4x1.5x0.2 mm(3)), depending on the cooling rate. alpha-PbF2 was grown on a seed crystal. The grown layer of about 1 mm in thickness has no visual inclusions and cracks.