Chemical elements
  Copper
    Isotopes
    Energy
    Production
    Application
    Physical Properties
    Chemical Properties
    Cuprous Compounds
      Cuprous hydride
      Cuprous fluoride
      Cuprous chloride
      Cuprous bromide
      Cuprous iodide
      Copper suboxide
      Cuprous oxide
      Cuprous hydroxide
      Cuprous sulphide
      Cuprous sulphite
      Cuprous sulphate
      Cuprous selenide
      Cuprous telluride
      Cuprous nitride
      Cuprous phosphide
      Cuprous arsenides
      Cuprous carbide
      Cuprous acetylide
      Cuprous carbonate
      Cuprous cyanide
      Cuprous thiocyanate
      Cuprous silicide
      Cuprous silicofluoride
      Ammonio-cuprous Derivatives
      Carbonyl cuprous sulphate
    Complex Copper Compounds
    Cupric Compounds
    PDB 1a2v-1bxu
    PDB 1bxv-1fwx
    PDB 1g3d-1j9t
    PDB 1jcv-1mfm
    PDB 1mg2-1paz
    PDB 1pcs-1sii
    PDB 1sjm-1w6w
    PDB 1w77-2afn
    PDB 2ahk-2dv6
    PDB 2dws-2ggp
    PDB 2ghz-2mta
    PDB 2nrd-2vm3
    PDB 2vm4-2yah
    PDB 2yam-3bkt
    PDB 3bqv-3fyi
    PDB 3g5w-3mie
    PDB 3mif-3t6v
    PDB 3t6w-9pcy

Cuprous sulphide, Cu2S






The Cuprous sulphide, Cu2S, occurs in nature as the mineral chalcocite or copper glance. It is synthesized by heating copper with sulphur, and fusing the product to decompose the cupric sulphide simultaneously produced. It can also be prepared from cupric sulphide by heating with hydrogen at 265° C., or with carbon dioxide at 130° to 150° C.; and from copper by the action of sulphuric acid at 124° C., or of a solution of ammonium sulphide in absence of air. It is also formed by heating cupric sulphide with sodium arsenite, sodium mono- thioarsenate being produced simultaneously:

2CuS + Na3AsO3 = Cu2S + Na3AsSO3.

The mineral crystallizes in the rhombic system, its density being 5.7 to 5.8. The artificial substance forms dark-grey octahedra belonging to the cubic system, its density being given as 5.52 to 5.58, and 5.785 (20° C.). An evolution of 0.9 Cal. per gram-molecule attends the transformation of the rhombic into the cubic form, the transition-point being 103° C. Its melting-point is given as 1057° C. (in sulphur-vapour), 1091° C., 1096° C. (in an atmosphere of hydrogen sulphide), 1114° C., and 1135° C., and its mean specific heat as 0.1212 between 9° and 97° C. It is very slightly soluble in water, but is soluble in concentrated nitric acid and sulphuric acid with decomposition. The heat of formation evolved in the direct combination of the elements is 19.0 Cal.

When suspended in a solution containing both ammonia and ammonium (or other) salts, air at atmospheric pressure oxidizes cuprous sulphide to cupric sulphate and thiosulphate, the reaction being slower than with cupric sulphide. In suspension in neutral or acidic solutions, cupric sulphate is produced, the reaction being less energetic than in presence of ammonia, and up to 160° C. requiring compressed air.

With sodium monosulphide cuprous sulphide forms a double salt of the formula Na2S,Cu2S. This compound melts at 700° C.


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