Chemical elements
    Physical Properties
    Chemical Properties
    Amorphous Carbon
      Lampblack and Soot
      Retort Carbon
      Animal Charcoal
      Physical Properties
      Chemical Properties
      Fusion and Vaporisation

Preparation of Amorphous Carbon

Amorphous carbon may be formed in a variety of ways, but its preparation in a state of purity is difficult. It is liberated in the following reactions:

  1. Decomposition of carbonaceous matter at high temperature (sugar, vegetable and animal charcoal, coke).
  2. Deposition from dissociated hydrocarbon vapours (lampblack, soot, gas-carbon).
  3. Explosive decomposition of endothermic compounds, e.g. acetylene.
  4. Deposition in electrolysis:

    1. at anode in electrolysis of silver acetylide;
    2. at kathode in electrolysis of concentrated sulphuric acid with carbon electrodes;
    3. at kathode in electrolysis of fused BaCO3 + BaCl2 at 600° C.
  5. Reduction of CO and CO2 by metals: e.g. CO2 by magnesium, calcium and the alkali metals, and CO by iron at high temperature.
  6. Decomposition of CO:

    1. by heat at 1690° C. into CO2 and free carbon;
    2. by radium emanation into O2, CO2, and carbon.
Sugar-charcoal and lampblack yield the purest forms of amorphous carbon, because they need contain no mineral impurity.

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