Chemical elements
  Silver
    Isotopes
    Energy
    Production
    Application
    Physical Properties
    Chemical Properties
      Silver fluoride
      Silver subfluoride
      Silver chloride
      Silver subchloride
      Photohalides
      Silver bromide
      Silver oxybromide
      Silver subbromide
      Silver iodide
      Silver hypochlorite
      Silver chlorite
      Silver chlorate
      Silver perchlorate
      Silver bromate
      Silver perbromate
      Silver iodate
      Silver periodates
      Silver suboxide
      Silver monoxide
      Higher oxides
      Silver subsulphide
      Silver sulphide
      Silver sulphite
      Silver sulphate
      Silver selenide
      Silver telluride
      Silver thiosulphate
      Silver dithionate
      Silver azide
      Silver hyponitrite
      Silver nitrite
      Silver nitrate
      Silver phosphides
      Silver hypophosphate
      Silver orthophosphate
      Silver pyrophosphate
      Silver metaphosphate
      Silver arsenite
      Silver arsenate
      Silver carbide
      Silver carbonate
      Silver cyanide
      Silver thiocyanate
      Silver borate
    PDB 1aoo-3kso

Silver sulphide, Ag2S






The Silver sulphide, Ag2S, occurs in nature as argentite, and also in combination with many other sulphides. It is formed by direct synthesis from its elements at ordinary temperatures, and also by immersion of the metal in solutions of alkali-metal poly sulphides. It can be prepared in cubic crystals by passing sulphur-vapour over heated silver, or by the action of hydrogen trisulphide, H2S3, on silver oxide. It is the only definite compound produced by fusion of mixtures of silver and sulphur in different proportions. The black, amorphous form is precipitated by the action of hydrogen sulphide or a soluble sulphide on a solution of a silver salt. It is also produced by the action of hydrogen sulphide on metallic silver, a reversible reaction.

The melting-point of the sulphide is given as 812° C., 815° C., and 834° C. It is the most insoluble of the silver salts, its solubility corresponding with 1.2×10-16 gram-atom of silver per litre. When heated with Silver sulphate at 300° C., both salts are reduced to metallic silver. In the fused state it is miscible with molten silver in all proportions. When heated in vacuum, it decomposes into its elements rapidly at 810° C.


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