Determination of phase fields in the CsBr-Cs2ZnBr4-Cs2CdBr4-Cs2HgBr4 quaternary system

Phase equilibria in the CsBr-Cs2ZnBr4-Cs2CdBr4-Cs2HgBr4 quaternary system were studied by differential thermal analysis. The CsBr-Cs2ZnBr4-Cs2HgBr4 ternary system has a ternary eutectic, E1, at ∼83 mol % Cs2HgBr4, 2 mol % Cs2ZnBr4, and 15 mol % CsBr with a melting point of ∼415°C. The CsBr-Cs2ZnBr4-Cs2CdBr4 ternary system has a ternary eutectic, E2, at ∼53.5 mol % Cs2CdBr4, 1.5 mol % Cs2ZnBr4, and 45 mol % CsBr with a melting point of ∼450°C. The polythermal section Cs3ZnBr5-Cs2CdBr4-Cs2HgBr4 in the CsBr-Cs2ZnBr4-Cs2CdBr4-Cs2HgBr4 quaternary system was constructed and investigated. This section is a quasi-ternary system and is characterized by the formation of regions of solid solutions Cs2ZnxCdyHg1−x − yBr4 and solid solutions based on Cs3ZnBr5. The liquidus surface of the quaternary system consists of three fields of primary crystallization of cesium bromide, a solid solution Cs2ZnxCdyHg1−x − yBr4, and a solid solution based on Cs3ZnBr5.