Chemical elements
    Amorphous Sulphur
    Colloidal Sulphur
    Physical Properties
    Chemical Properties
      Hydrogen Sulphide
      Metal Polysulphides
      Hydrogen Polysulphides
      Hydrogen Pentasulphide
      Hydrogen Trisulphide
      Hydrogen Disulphide
      Sulphur Monofluoride
      Sulphur Tetrafluoride
      Sulphur Hexafluoride
      Sulphur Monochloride
      Sulphur Dichloride
      Sulphur Tetrachloride
      Sulphur Monobromide
      Thionyl Fluoride
      Sulphuryl Fluoride
      Fluorosulphonic Acid
      Thionyl Chloride
      Sulphuryl Chloride
      Sulphur Oxytetrachloride
      Pyrosulphuryl Chloride
      Chlorosulphonic Acid
      Thionyl Bromide
      Sodium Sulphoxylate
      Sulphur Dioxide
      Sulphurous Acid
      Sulphur Trioxide
      Pyrosulphuric Acid
      Sulphuric Acid
      Persulphuric Anhydride
      Persulphuric Acid or Perdisulphuric Acid
      Permonosulphuric Acid
      Amidopermonosulphuric Acid
      Thiosulphuric Acid
      Polythionic Acids
      Dithionic Acid
      Trithionic Acid
      Tetrathionic Acid
      Pentathionic Acid
      Wackenroders Solution
      Hexathionic Acid
      Polythionic Acids
      Sulphur Sesquioxide
      Hydrosulphurous Acid
      Nitrogen Sulphide
      Nitrogen Persulphide
      Nitrogen Pentasulphide
      Nitrogen Chlorosulphide
      Trithiazyl Chloride
      Thiotrithiazyl Chloride
      Dithiotetrathiazyl Chloride
      Nitrogen Bromosulphide
      Thiotrithiazyl Bromide
      Thiotrithiazyl Iodide
      Thiotrithiazyl Nitrate
      Thiotrithiazyl Hydrogen Sulphate
      Thiotrithiazyl Thiocyanate
      Sulphonic Acids
      Amidosulphonic Acid
      Imidosulphonic Acid
      Nitrilosulphonic Acid
      Hydroxylamine-monosulphonic Acid
      Nitrososulphonic Acid
      Hydroxylamine-disulphonic Acid
      Hydroxylamine-isodisulphonic Acid
      Hydroxylamine-trisulphonic Acid
      Dihydroxylamidosulphonic Acid
      Sulphazinic Acid
      Sulphazotinic Acid
      Dehydrosulphazotinic Acid
      Nitrosulphonic Acid
      Nitrosulphonyl Chloride
      Nitrosulphonic Anhydride
      Nitrosulphuric Acid
      Nitrosodisulphonic Acid
      Sulphonitronic Acid
      Sulphates of Hydroxylamine
      Hydroxylamine Dithionate
      Hydrazine Dithionate
      Hydrazine Amidosulphonate
      Carbon Subsulphide
      Carbon Monosulphide
      Carbon Disulphide
      Thiocarbonic Acid
      Ammonium thiocarbonate
      Thiolcarbonic Acid
      Xanthic Acid
      Perthiocarbonic Acid
      Sodium perthiocarbonate
      Carbonyl Sulphide
      Thiocarbonyl Chloride
      Thiocarbonyl Tetrachloride or
      Carbon Hexachlorosulphide
      Trichloromethyl Disulphide
      Thiocarbonyl Sulphochloride
      Carbon Bromosulphide
      Amino-derivatives of Thiocarbonic Acid
      Dithiocarbamic Acid
      Azidodithiocarbonic Acid
      Cyanogen Monosulphide
      Cyanogen Trisulphide
      Sulphur Thiocyanate
      Disulphur Dithiocyanate
      Thiocyanic Acid
      Dithiocyanic Acid
      Trithiocyanuric Acid
      Perthiocyanic Acid

Sulphur Monobromide, S2Br2

Sulphur Monobromide, or Disulphur Dibromide, S2Br2, is the only definite bromide of sulphur. It is obtained on heating an equi-atomic mixture of sulphur and bromine at 100° C. in a sealed tube. The product is distilled under reduced pressure and collected in a dry receiver. Combination of the two elements can also occur at a lower temperature, as is shown by the fact that sulphur dissolved in bromine is present as sulphur monobromide molecules and not as free sulphur, proof being possible by cryoscopic measurements.

Sulphur monobromide is also formed when sulphur monochloride and potassium bromide are heated together in a sealed tube. It is a garnet-red, oily liquid, which does not wet glass; its density is 2.6355 at 20° C.; its melting-point is -46° C. and its boiling-point 54° C. at 0.18 mm.; at higher pressures the boiling-point is inconstant, due to dissociation. The refractive index, n7820, is 2.6268.

Sulphur monobromide is a slightly exothermic substance with respect to its elements. It is decomposed by water in an analogous manner to the monochloride, but more readily. It dissolves sulphur readily on warming, depositing some of the solid again on cooling. Yellow phosphorus dissolves in the cold liquid, but on warming explosive chemical action sets in. Iodine monochloride reacts giving iodine bromide and sulphur monochloride.

In the presence of alkali the bromide decomposes with formation of a sulphite, a bromide and sulphur:

2S2Br2 + 6KOH = 4KBr + K2SO3 + 3S + 3H2O.

Existence of other Bromides

At one time the existence of compounds SBr2 and SBr4 was suspected, but the evidence is insufficient and unconvincing. The curves representing the vapour pressures and the freezing-points of mixtures of sulphur monobromide and bromine give no indication of the formation of any compound. The evidence thus supplied merely indicates that neither dibromide nor tetrabromide is formed on mixing the monobromide and bromine.
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