IMIDOSULPHOXATES. IQ7 



a way essentially the same as that followed by the normal mercury 

 sodium salt. Most gradual heating in a current of dried air to a 

 temperature of 170° fails to expel more than four-hfths of the water, 

 in consequence no doubt of hydrolysis. 



It is much more readily dissolved by hydrochloric acid tlian by 

 nitric or sulphuric acid. From its hydrochloric-acid solution it can not 

 be recovered by neutralisation, being almost instantly decom])osed, like 

 the normal mercuric sodium salt. It is converted by sodium hydrox- 

 ide into mercuric oxide insoluble, and mercuric disodium imidosid- 

 phonate dissolved. Its basic composition is at once demonstrated by 

 the action on it of sodium chloride, which leaves insoluble mercuric 

 oxide, and dissolves the rest, probably, as the two salts, mercuric 

 sodium imidosulphonate and mercuric sodium chloride. Trisodium 

 imidosulphonate dissolves it, but not to a large extent. When tlie 

 solution of this salt is concentrated, a little mercuric oxide may separate, 

 but enough water added causes this gradually to dissolve. When the 

 trisodium salt is added to the oxymercuric sodium salt still in its 

 mother-liquor, free dissolution at once occurs; but without the mother- 

 liquor the reaction is as above stated. 



The composition of the salt is expressed, as the following analytical 

 results show, by the formula — OHg2N(S03)o]Sra,(OH2).2— which has, 

 however, to be doubled to display its constitution. The water comes 

 out low, partly because of loss by efflorescence, but mainly by getting 

 •fixed through hydrolysis. 



