Zu den pseudobinären Zustandssystemen Bi2Ch3-BiX3 und den ternären Phasen auf diesen Schnitten (Ch = S, Se, Te; X = Cl, Br, I), I: Bismutsulfidhalogenide/The Pseudobinary Systems Bi2Ch3-BiX3 and the Ternary Phases on their Boundary Lines (Ch = S, Se, Te; X = Cl, Br, I), I: Bismuth Sulfide Halides

Abstract

The phase diagrams of the systems Bi2S3-BiX3 were constructed from results of DTA and total pressure measurements and x-ray analysis. The phases: BiSCl, Bi4S5Cl2 and Bi19S27Cl3 for X = Cl; BiSBr and Bi19S27Br3 for X = Br; BiSI and Bi19S27I3 for X = I exist on the boundary lines. The enthalpies of formation and standard entropies of the phases follow from the coexistence decomposition pressure functions. The data are: ΔH°B(BiSClf,298) =−49,6 ± 1,6 kcal/mol S°(BiSClf,298) = 30,3 ± 2,5 cal/K·mol ΔH°B(Bi4S5Cl2,f,298) =−144,4 ± 3 kcal/mol S°(Bi4S5Cl2,f,298) = 114,0 ± 4,6 cal/K·mol ΔH°B(Bi19S27Cl3,f,298) = −520 ± 10 kcal/mol S°(Bi19S27Cl3,f,298) = 490 ± 10 cal/K·mol ΔH°B(BiSBrf,298) = −40,2 ± 1,4 kcal/mol S°(BiSBrf,298) = 32,0 ± 3 cal/K·mol ΔH°B(Bi19S27Br3,f,298) = −493,6 ± 6,7 kcal/mol S°(Bi19S27Br3,f,298) = 499,8 ± 17 cal/K·mol ΔH°B(BiSIf,298) =−27,8 ± 1,4 kcal/mol S°(BiSIf,298) = 36,1 ± 2,5 cal/K·mol ΔH°B(Bi19S27I3,f,298) =−464,4 ± 15 kcal/mol S°(Bi19S27I3,f,298) = 502,7 ± 15 cal/K·mol