II Halide Sulfide

The mercury chloride sulfide 7-Hg3S2Cl2 is obtained by either quenching a mixture of mercury(II) sulfide vapor from 750°C. or by the reaction of a dilute alkaline solution of mercury(II) chloride with carbon disulfide. The conditions for the preparation of Hg3S2Cl2 are given in Table IV. 

The 7 modification has been found to be unstable under normal conditions.8 The light-yellow crystals decompose slowly within months. Crystallographic data for the orthorhombic compounds are a = 9.094 A., b = 16.843 A., c = 9.349 A., and 2 = 8. 

Various lead halide sulfides are reported in the literature. They precipitate when acidic solutions of lead halides react with hydrogen sulfide. Most probably the lead(II) chaicogenide halides described below are the only stable ones among these compounds. The conditions for the syntheses of these materials are given in Table V. 

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