IMIDOSULPHONATES. 97 



prepared from the mercury sodium salts, but we have only made 

 ourselves familiar with the mercury barium salt, particularly noticed 

 by Berglund. It is a lustrous, crystalline, dense salt, almost insoluble 

 in cold water. 



Mercuni (Hhiiayotjcn imidosulphonate. — When mercury barium 

 imidosulphonate is treated with dilute sul})huric acid, not in excess of 

 the barium, it appears to be sbirply converted into liarium sulphate 

 and mercury hydrogen imidosulphonate. This observation made by 

 Bero'lund we have confirmed and extended. We worked quantita- 

 tively and were careful to use the sul})huric acid in slight deficit, and 

 to filter quickly, \'erv easy to do in consequence of the dense state of 

 the barium sulphîîte. But already hydrolysis of the imidosul])honate 

 into sulphate and amidosul]3honic acid had begun when we tested the 

 filtrate. It progressed steadily, so that in ten minutes the sulphuric 

 acid had grown to a considerable quantity, showing that mercury 

 hydrogen imidosulphonate is stable to a less degree even than sim])le 

 hydrogen imidosulphonate. In about ten minutes also, the solution 

 began to grow turbid, and let fall an oxymercuric unit, probably 

 amidosulphonate. The fresh solution when almost neutralised with 

 potassium hydroxide gave a slight white turbidity, doubtless of oxy- 

 mercuric potassium imidosulphonate, which dissolved when a little 

 more alkali was added. The slightly alkaline solution, thus prepared, 

 soon began to deposit minute crystals which we fully identified as 

 mercury dipotassium imidosulphonate. Thus, we had proved, so far 

 as might be done, that the fresh filtrate from the barium sulphate is 

 really a solution of mercury hydrogen imidosulphonate. 



Oxijmercuric hiidrcxjeu imidosulphonate. — A second salt of mercury 

 and hydrogen can be readily obtained, which is at once ])asic and acid 

 salt, as its name indicates. Highly concentrated mercuric nitrate 

 solutions, even when free as possible from nitric acid, dissolve, to clear 



