AMIDOSULPHOXIC ACID. 255 



two-thirds normal potassium imidosulphonate, but there is always a 

 marked quantity of the corresponding ammonium salt, as well as a 

 little sulphate. Just on melting, the amidosulphonate evidently decom- 

 poses, thus: — 2H. 2 NS0 3 K = NH 4 N(S0 3 lv) L ,, which almost at once 

 begins to evolve ammonia. The explanation of the production of 

 ammonium salt and of sulphate must be the same as that in the case 

 of the barium salt next described, but in heating the potassium salt, 

 anything volatile but ammonia was hardly to be recognised. 



The barium salt. — According to Berglund, the behaviour of the 

 barium salt, when heated, is radically different from that of the alkali 

 salts, for, whereas these slowly decompose at 160-170° into ammonia 

 and imidosulphonate, which then becomes sulphate, the barium salt 

 suiters no change up nearly to 200°, and then decomposes into sulphate, 

 ammonia, nitrogen, and sulphur dioxide, while no imidosulphonate 

 c:m be detected. But Berglund was mistaken ; there is a difference, 

 but not a fundamental one, for imidosulphonate is formed. 



Barium amidosulphonate decomposes without suffering any kind 

 of fusion. As Berglund stated, only a little below 200° does ammonia 

 begin to come off from it, and not till about 240° does this freely 

 escape. At about 275°, there is production of a sublimate of orange 

 nitrogen sulphide, a very little sulphur, a small sublimate of ammonium 

 pyrosulphite, and, no doubt, nitrogen, along with the ammonia. 

 Although, now, the salt looks little changed, it has lost considerably 

 in weight (7.5 o per cent., observed), and become caked. Water 

 dissolves out of it quite a quantity of the two-thirds normal am- 

 monium imidosulphonate. When the salt is less heated, water 

 dissolves out of the mass a little barium imidosulphonate, as 

 well as ammonium salt ; but after the greater heating, no soluble 

 barium salt is left. The explosive nitrogen sulphide was quite 

 certainly identified as such. To decompose the barium salt without 



