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

Amidosulphonic Acid, NH2.SO3H

Amidosulphonic Acid, NH2.SO3H, may be obtained by the action of sulphur trioxide on dry ammonia. When an aqueous solution of hydroxylamine hydrochloride is saturated with sulphur dioxide and afterwards evaporated, amidosulphonic acid is obtained. Potassium imidosulphonate, NH(SO3K)2, and potassium nitrilosulphonate, N(SO3K)3, are both decomposed by hot water with formation of potassium amidosulphonate:

NH(SO3K)2 + H2O = NH2.SO3K + HO.SO3K,
N(SO3K)3 + 2H2O = NH2.SO3K + 2HO.SO3K.

Amidosulphonic acid may also be prepared by passing sulphur dioxide into an aqueous solution of sodium nitrite containing sodium carbonate, until the solution is acid to litmus; the nitrilosulphonate which is formed is hydrolysed by the addition of a little concentrated sulphuric acid, amidosulphonate and acid sulphate being formed. The solution is neutralised by the addition of sodium carbonate and the sodium sulphate formed separated by crystallisation; the addition of a large excess of concentrated sulphuric acid to the solution then results in the precipitation of amidosulphonic acid.

Amidosulphonic acid is a colourless, odourless, crystalline solid, specific gravity 2.03 at 12° C. It decomposes to a large extent during melting but has an apparent melting-point of 205° C. It is slowly soluble in water, requiring five parts of water at 0° C. and half this amount at 70° C. to dissolve it. It is stable in air and not deliquescent. Although it is not precipitated by solutions of barium chloride it retards the precipitation of small quantities of sulphuric acid by barium chloride. It forms a compound with oxide or nitrate of mercury, which is insoluble in dilute nitric acid and probably has the composition Hg3N2(SO3H)2(OH)2.2H2O. When amidosulphonic acid, or any of its salts, is heated, partial conversion into imidosulphonate and ammonia occurs

2NH2.SO3H = NH(SO3H)2 + NH3,

and partial conversion into sulphate and gaseous products. Thus, in the case of the barium salt, the decomposition may be represented by the equation:

3Ba(SO3.NH2)2 = 3BaSO4 + NH(SO3.NH4)2 + NH3 + NS + N.

The potassium salt reacts in the cold with an equivalent amount of hypochlorous acid to form potassium chloramidosulphonate, NHCl.SO3K, which may be isolated by evaporation to small bulk in vacuo and precipitation with alcohol. It is a comparatively stable, hygroscopic, crystalline salt, hydrolysed by mineral acids to form ammonium chloride and sulphuric acid. The corresponding bromine compound is similar in properties. Barium forms a less stable chloro-compound.

Amidosulphonic acid reacts quantitatively with the alkalis, and with carbonates and borates, and its use as a primary standard in volumetric analysis has been suggested.

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