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

Ammonium thiocarbonate, (NH4)2CS3

Ammonium thiocarbonate, (NH4)2CS3, may be prepared by digesting ammonium pentasulphide with carbon disulphide under a reflux condenser; a white deposit of ammonium monosulphide first forms on the condensing surface and is gradually converted into the thiocarbonate, becoming pale orange-coloured. On exposure to moist air it turns red.

The thiocarbonates of the alkali and alkaline earth metals may also be obtained by the action of carbon disulphide on the corresponding hydroxides under certain conditions. On shaking carbon disulphide with aqueous sodium hydroxide, a deep red solution is obtained, the reaction being facilitated by warming to 80° C., and especially by the presence of emulsifying agents. The solution contains sodium trithio-carbonate sufficient in amount to satisfy the equation:

3CS2 + 6NaOH = 2Na2CS3 + Na2CO3 + 3H2O.

No dithiocarbonate is formed, nor in freshly prepared solutions are polysulphides or thiosulphates present. With oxidising agents such as hydrogen peroxide or chlorine, the red solution yields sulphates, whilst salts of the heavy metals give coloured precipitates which are unstable when moist, decomposing to carbon disulphide and the metal sulphide.

It was generally supposed that the removal of carbon disulphide from crude coal gas when purified by lime was due to its absorption by calcium sulphide with the formation of calcium thiocarbonate, but Yeoman suggests that it is the perthiocarbonate, CaCS4, which is formed. This suggestion accounts for the necessity of the presence of some oxygen in order that absorption may take place.

The thiocarbonates of the alkali and alkaline earth metals are soluble in water. The alkali thiocarbonates are yellow in colour. In concentrated solution these salts are fairly stable, but in dilute solution they are gradually decomposed, forming the carbonate and hydrogen sulphide.

Under certain conditions thiocarbonates behave like simple sulphides; thus, benzoyl chloride and a thiocarbonate in equimolecular proportions yield benzoyl disulphide, which substance is also formed by the interaction of benzoyl chloride and potassium hydrogen sulphide followed by oxidation. The complex salts of the thiocarbonates are more stable than the simple salts.

Thiocarbonates, especially the alkali thiocarbonates, are used in agriculture to prevent certain diseases, notably phylloxera of the vine. It is carbon disulphide which is the active material of these fungicides.

It has been shown that when a solution of potassium thiocarbonate is boiled in an atmosphere of nitrogen, the following change takes place:-

K2CS3 = K2S + CS2,

the sulphide subsequently undergoing hydrolysis, thus:

K2S + 2H2O = 2KOH + H2S

In the presence of air or oxygen, however, the reaction is as follows:- 2K2CS3 + 2H2O + 2O2 = K2S2O3 + K2CO3 + CS2 + 2H2S,

and in an atmosphere of carbon dioxide:

K2CS3 + CO2 + H2O = K2CO3 + CS2 + H2S.

It is believed that the reaction

K2CS3 + 3H2O = K2CO3 + 3H2S

cannot take place.

When carbon disulphide is heated with sodium alone in a sealed tube at 150° C., no reaction other than slight superficial tarnishing of the metal occurs; with a sodium-potassium alloy yellowish-brown explosive crusts are formed. When the liquid is shaken with sodium amalgam (0.8 per cent. Na) and the mixture then treated with 90 per cent, alcohol, a solution containing a complex mixture of compounds is obtained, from which by treatment with methyl chloride the following compounds may be isolated: methyl sulphide, two isomeric methyl tetrathio-oxalates, methyl methylxanthate, tetramethylthiolethylene and methyl trithiocarbonate ( 224° C. at 760 mm.). Similar products (except the xanthate) may be obtained by allowing carbon disulphide to react with sodium in solution in liquid ammonia and treating the resulting brown mass with methyl sulphate.

Salts and esters of the intermediate thio-acids are known, being prepared from carbon disulphide or carbon oxysulphide.

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