Chemical elements
  Cadmium
    Isotopes
    Energy
    Production
    Application
    Physical Properties
    Chemical Properties
      Cadmium Fluoride
      Cadmium Chloride
      Cadmium Bromide
      Cadmium Iodide
      Cadmium Chlorate
      Cadmium Perchlorate
      Cadmium Bromate
      Cadmium Iodate
      Cadmium Periodate
      Cadmium Suboxide
      Cadmium Oxide
      Cadmium Hydroxide
      Cadmic Hydroxide
      Cadmium Peroxide
      Cadmium Sulphide
      Cadmium Sulphite
      Cadmium Sulphate
      Cadmium Thiosulphate
      Cadmium Dithionate
      Cadmium Selenide
      Cadmium Selenites
      Cadmium Selenate
      Cadmium Telluride
      Cadmium Tellurite
      Cadmium Tellurate
      Cadmium Chromite
      Cadmium Chromate
      Cadmium Dichromate
      Cadmium Molybdate
      Cadmium Tungstate
      Cadmium Nitride
      Cadmium Azide
      Cadmium Amide
      Cadmium Nitrite
      Cadmium Nitrate
      Cadmium Phosphide
      Cadmium Hypophosphite
      Cadmium Orthophosphate
      Cadmium Pyrophosphate
      Cadmium Thiophosphates
      Cadmium Arsenide
      Cadmium Arsenite
      Cadmium Arsenates
      Cadmium Metantimonate
      Cadmium Carbonate
      Cadmium Thiocarbonate
      Cadmium Cyanide
      Cadmium Silicate
      Cadmium Borates
    PDB 1a4k-1exq
    PDB 1f48-1ihu
    PDB 1ii0-1mhu
    PDB 1mms-1qvg
    PDB 1qy0-1wb6
    PDB 1wje-2avp
    PDB 2b3p-2j6e
    PDB 2jdz-2x05
    PDB 2x09-3ccj
    PDB 3ccl-3ggf
    PDB 3h1u-3p5v
    PDB 3p5w-8ice

Cadmium Oxide, CdO






Cadmium Oxide, CdO, occurs occasionally in nature as black, shining, regular octahedra of density 6.15 and hardness 5.

When cadmium is heated in the air it forms. the characteristic cinnamon-brown amorphous oxide, which can also be obtained by calcining the hydroxide or carbonate, or by heating cadmium fluoride in air or steam. Regnault obtained cadmium oxide (apparently the amorphous form) by heating the metal in steam.

The crystalline oxide may form when cadmium is sublimed in a tube containing air. It has been obtained in black crystalline cubes by burning cadmium in oxygen, in deep red cubes by heating the oxide similarly, and in microscopic octahedra by igniting cadmium nitrate.

The density of the artificial crystals has been variously given from 6.25 to 8.18.

Cadmium oxide is reduced by hydrogen at 400° C., and, though the action is reversible, the reduction takes place more easily than with zinc oxide.

Cadmium oxide is also more easily reduced by carbon than zinc oxide, and magnesium reduces it at a red heat. Chlorine, in the heat, readily converts it into the chloride, and when heated with sulphur or phosphorus vapour, cadmium sulphide or phosphides result.

It volatilises slowly or dissociates at 900°-1000° C., and the rate of loss becomes less as the oxide becomes denser or more crystalline. It is very insoluble in water, though acids dissolve it readily.

[Cd]+(O) = [CdO] (amorphous)+57.0 Cal.
[Cd]+(O) = [CdO] (mainly crystalline)+63.0 Cal.

The heat of solution in aqueous hydrofluoric acid is 23.450 Cal.


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