Chemical elements
    Physical Properties
    Chemical Properties
      Alkali Phosphides
      Alkaline Earth Phosphides
      Copper Silver and Gold Phosphides
      Zinc Group Phosphides
      Aluminium Phosphide
      Titanium Group Phosphides
      Tin Phosphides
      Lead Phosphides
      Arsenic Phosphides
      Antimony Phosphides
      Bismuth Phosphides
      Chromium Phosphides
      Molybdenum and Tungsten Phosphides
      Manganese Phosphides
      Iron Phosphides
      Cobalt Phosphides
      Phosphonium Chloride
      Phosphonium Bromide
      Phosphonium Iodide
      Hydrogen Phosphides
      Phosphorus Trifluoride
      Phosphorus Pentafluoride
      Phosphorus Trifluorodichloride
      Phosphorus Trifluorodibromide
      Fluophosphoric Acid
      Phosphorus Dichloride
      Phosphorus Trichloride
      Phosphorus Pentachloride
      Phosphorus Chlorobromides
      Phosphorus Chloroiodides
      Phosphorus Tribromide
      Phosphorus Pentabromide
      Phosphorus Diiodide
      Phosphorus Triiodide
      Phosphorus Oxytrifluoride
      Phosphorus Oxychloride
      Pyrophosphoryl Chloride
      Metaphosphoryl Chloride
      Phosphoryl Monochloride
      Phosphoryl Dichlorobromide
      Phosphoryl Chlorodibromide
      Phosphoryl Tribromide
      Metaphosphoryl Bromide
      Phosphoryl Oxyiodides
      Phosphorus Thiotrifluoride
      Phosphorus Thiotrichloride
      Phosphorus Thiotribromide
      Mixed Phosphorus Thiotrihalides
      Phosphorus Suboxides
      Phosphorus Trioxide
      Phosphorus Dioxide
      Phosphorus Pentoxide
      Hypophosphorous Acid
      Phosphorous Acid
      Meta- and Pyro-phosphorous Acids
      Hypophosphoric Acid
      Tetraphosphorus Trisulphide
      Diphosphorus Trisulphide
      Tetraphosphorus Heptasulphide
      Phosphorus Pentasulphide
      Phosphorus Oxysulphides
      Phosphorus Thiophosphites
      Phosphorus Thiophosphates
      Phosphorus Selenophosphates
      Phosphorus Sulphoselenides
      Diamidophosphorous Acid
      Phosphorus Triamide
      Monamidophosphoric Acid
      Diamidophosphoric Acid
      Triamidophosphoric Acid
      Dimetaphosphimic Acid ≡P=
      Trimetaphosphimic Acid
      Tetrametaphosphimic Acid
      Penta- and Hexametaphosphimic Acid
      Monamidodiphosphoric Acid
      Diamidodiphosphoric Acid
      Triamidodiphosphoric Acid
      Nitrilotrimetaphosphoric acid
      Monothioamidophosphoric Acids
      Thiophosphoryl Nitride
      Di- Tri-imido- and -amido-thiophosphates
      Imidotrithiophosphoric Acid =
      Phosphorus Chloronitrides
      Triphosphonitrilic Chloride
      Tetraphosphonitrilic Chloride
      Pentaphosphonitrilic Chloride
      Hexaphosphonitrilic Chloride
      Heptaphosphonitrilic Chloride
      Triphosphonitrilic Bromide
      Phosphorus Halonitrides
      Phosphorus Nitride
      Pyrophosphoric Acid
      Phosphoric acids
    Slow Oxidation
    Phosphatic Fertilisers

Phosphorus Thiotribromide, PSBr3

Phosphorus Thiotribromide, PSBr3, has been prepared in a number of different ways:—

  1. By the action of phosphorus pentabromide on hydrogen sulphide, according to the equation

    PBr5 + H2S = PSBr3 + 2HBr
  2. By distillation of the tribromide with sulphur.
  3. By combination of the pentabromide with the pentasulphide:—

    P2S5 +3PBr5 = 5PSBr3

    The product may be freed from pentabromide by washing with warm water and dried by dissolving in CS2 and standing over CaCl2.
  4. By a reaction between ammonium trithiophosphate and hydrogen bromide.


The compound crystallised from carbon disulphide in yellow octahedra, having a density of 2.7 to 2.87 and a melting-point of +36.4° to +39° C. It gives off a pungent vapour, and distils at about 212° C. with some decomposition at first into PBr3, then PSBr3 follows, and finally there is a residue of sulphur and phosphorus. It is only slightly hydrolysed by water even at 100° C., the products being phosphoric acid, hydrogen bromide and some sulphide, together with some sulphur and phosphorous acid. Alcoholysis is said to yield ethyl thiophosphate, (C2H5)3PSO3.

Thiophosphoryl bromide dissolves sulphur and mixes with other halides such as phosphorus trichloride, also with ether, chloroform and carbon disulphide.

Several other thiobromides of phosphorus have been prepared, which can be regarded as derivatives of pyrophosphoric acid. Diphosphorus monothiohexabromide, P2SBr6, is prepared by distilling PSBr3, and appears as a yellow oil which can be solidified to crystals melting at -5° C. The boiling-point is 205° C. When mixed with water it gives a crystalline hydrate melting at +35° C. P2S3Br4 (diphosphorus trithiotetrabromide) is prepared by the action of bromine on P4S6 dissolved in carbon disulphide. In appearance and properties it is very similar to the other thiobromides.
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