Chemical elements
  Selenium
    Isotopes
    Energy
    Production
    Application
    Allotropy
    Colloidal
    Physical Properties
    Chemical Properties
      Hydrogen Selenide
      Selenium Fluorides
      Selenium Monochloride
      Selenium Tetrachloride
      Selenium Monobromide
      Selenium Tetrabromide
      Selenium Chlorobromides
      Selenium Oxyfluoride
      Selenium Oxychloride
      Sulphur Selenium Oxytetrachloride
      Selenium Oxybromide
      Chloroselenic Acid
      Selenium Dioxide
      Selenious Acid
      Selenium Trioxide
      Selenic Acid
      Selenates
      Perselenic Acid
      Selenium Sulphoxide
      Selenotrithionic Acid
      Diselenotrithionic Acid
      Selenopentathionic Acid
      Selenium Nitride
      Nitrosylselenic Acid
      Phosphorus Subselenide
      Phosphorus Monoselenide
      Tetraphosphorus Triselenide
      Phosphorus Triselenide
      Phosphorus Pentaselenide
      Phosphorus Chloroselenide
      Selenophosphates and Oxyselenophosphates
      Carbon Diselenide
      Carbon Subselenides
      Carbon Oxyselenide
      Carbon Sulphidoselenide
      Cyanogen Monoselenide
      Cyanogen Diselenide or Selenocyanogen
      Cyanogen Triselenide
      Selenocyanic Acid
      Ammonium Selenocyanate
      Caesium Triselenocyanate
      Copper Selenocyanate
      Lead Selenocyanate
      Magnesium Selenocyanate
      Mercurous Selenocyanate
      Mercuric Selenocyanate
      Potassium Selenocyanate
      Silver Selenocyanate
      Sodium Selenocyanate
      Zinc Selenocyanate
      Silicon Selenide
    Detection and Estimation

Selenium Nitride, Se4N4






Selenium Nitride, Se4N4 was first obtained in 1859 by saturating selenium tetrachloride with ammonia in the cold:

12SeCl4 + 64NH3 = 3Se4N4 + 48NH4Cl + 2N2.

It may also be prepared by passing a stream of dry ammonia into a 2 to 4 per cent, solution of selenyl chloride in benzene. The nitride is precipitated as a buff-coloured solid which becomes orange-red when dry. Some free selenium is deposited along with the nitride, the amount increasing with the concentration of the selenyl chloride solution. After washing the buff precipitate the free selenium may be extracted by means of potassium cyanide solution.

By each of these methods the nitride is obtained as a brick-red amorphous powder which, when dry, is highly explosive, detonating violently on slight touch, forming a cloud of red selenium; it is considerably more sensitive than mercury fulminate.

After investigating the action of liquid ammonia on a variety of selenium compounds, Strecker and Claus have come to the conclusion that the tetrahalides are the best initial materials for the preparation of selenium nitride. The action of liquid ammonia on selenium tetrabromide in the presence of carbon disulphide gives a good yield of the nitride.

Selenium nitride is insoluble in water, alcohol and ether, slightly soluble in carbon disulphide, benzene and glacial acetic acid. It is decomposed by caustic potash with the formation of potassium selenite, ammonia and free selenium. It reacts explosively with both chlorine and bromine. In the presence of carbon disulphide the action of bromine leads to the formation of a brownish-green hygroscopic substance having the composition SeN2Br4. If the bromine vapour is diluted with carbon dioxide, the nitride is converted into ammonium selenibromide, (NH4)2SeBr6, the formation of which appears to be due to the action of atmospheric moisture on a primary addition product. In similar circumstances chlorine yields a compound of composition SeNCl3. Iodine, whether solid or dissolved in ether or chloroform, has no action on selenium nitride.

A suitable solvent is not available for the determination of the molecular weight of the nitride, but evidence seems to favour a cyclic structure for the molecule Se4N4.


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