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

Thionyl Fluoride, SOF2

Thionyl Fluoride, SOF2, was first obtained pure by Moissan and Lebeau in 1900 by heating a mixture of arsenic pentafluoride and thionyl chloride in a glass tube at 100° C. for half an hour. The tube was cooled to -80° C. before re-opening, the liquid then being allowed to evaporate by cautiously allowing the temperature to rise, the thionyl fluoride, which boiled away at a little below 30° C., being collected over mercury. The gas was freed from traces of thionyl chloride and arsenic pentafluoride by passage through a spiral tube at -23° C., the fluoride passing over uncondensed:

2AsF5 + 5SOCl2 = 5SOF2 + 2AsCl5.

A modification of this method has been used by Steinkopf and Herold. An ice-cooled brass flask containing arsenic fluoride was fitted with a reflux condenser connected to a second condenser which led to a leaden vessel cooled to -50° or -60° C. The calculated quantity of thionyl chloride was gradually added to the arsenic fluoride and the flask slowly warmed to about 80° C., when the thionyl fluoride distilled into the cooled lead receiver, whilst the arsenic fluoride and chloride and thionyl chloride were held back by the reflux condenser.

Thionyl fluoride has also been obtained in excellent yield by the interaction of liquid hydrogen fluoride and nitrogen sulphide in the presence of a little copper oxide, the reaction being best effected in a copper bomb at 100° C. The gas, which issues on opening the bomb, can be collected in a receiver cooled by liquid air.

The fluoride is a colourless gas which fumes in moist air and has a pungent, unpleasant odour, recalling that of carbonyl chloride. It condenses at -30° C. to a liquid which on further cooling gives a solid of -110° C. Its vapour density corresponds with the formula SOF2. It is soluble in arsenic chloride, ether, benzene and turpentine.

When submitted, in a glass vessel, to the electric spark discharge, or when heated to 400° C., gradual decomposition sets in, with formation of sulphur dioxide and fluorine, the latter giving rise to silicon tetrafluoride, and the total change being representable by the equation:

SiO2 + 2SOF2 = SiF4 + 2SO2.

When not in contact with glass, e.g. in a tube of platinum, thionyl fluoride can be heated to a white heat without appreciable decomposition. Water causes a slow hydrolysis:

SOF2 + 2H2O = H2SO3 + 2HF.

At high temperatures hydrogen acts on the gas with formation of hydrogen fluoride, water, hydrogen sulphide and free sulphur. Chlorine in sunlight, or in contact with charcoal in a glass tube, gives rise to sulphuryl chloride and silicon fluoride. A mixture of thionyl fluoride with moist nitrogen trioxide in the presence of silica undergoes chemical change with formation of silicon fluoride and nitrosulphonic acid.

Sulphur and phosphorus do not affect the fluoride even at 500° C., but hot sodium causes gradual decomposition, with complete absorption.

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