96 



mVEES AND HAGA. 



Mercurij jtoiassiimi iiiiidosidphonafes. — Berglund jR-epared mercury 

 dipotassiiun imidosulplKjnate, Hg]Sr2(S03K)4, from tripotassium imido- 

 8iil])lionate. We liave prepared it from dipotassmm imidosulplioiiate 

 by adding mercuric oxide to it and heating the mixture with water, 

 filtering hot if necessary, and Jen vi ng the solution to cool. The salt, 

 which is nearly insoluble in cold water, separates out in very minute 

 needles, sometimes arranged loosely, sometimes in s[)herical tufts, and 

 is when dry of silvery lustre. 



Au oxyinercKfic potassium salt, analogous t(j the sodium sîdt 

 fp. 105), seems to be umong the products of the reaction between mer- 

 curic nitrate and potassium imidosulphonates, but we have not made 

 any study of it. 



The behaviour of mercur}' dipotassium imidosulphonate Avith 

 acids, as observed by us, is of interest in connection with the theory 

 of "the constitution of these salts, and we shall refer to it later on when 

 discussing that point ([>. 110). When the salt, in a state of paste 

 with water, is treated with nitric acid, it is converted into the very 

 slightly soluble dijMjtassium imidcjsidphonate, all its mercury dissolv- 

 ino- as mercuric nitrate. Washed and drained on a tile, the salt left 

 undissolved has been found to be free of mercury and of sulphate. 

 The same experiment can l)e carried out by the use of dilute «idphuric 

 acid, but less satisfactorily. The nitric acid used may be strong and 

 in excess, but i]ni sul|)huric acid nuist be dilute and not in excess, and 

 is apt to give a small precipitate of mercuric salt. Hydrochloric acid 

 exchana'es hydroiten foi" both metals, and effects extremely rai)id 

 hydrolysis. 



Mercunj Iniriiini, HgN.(k5(J:i).J)a., and other double niercunj iiuidosul- 

 plionaies. — Mercury dipotassium imidosulphonate gives, according to 

 Berglund, a series of doubles salts in wiiich the potassium has been 

 replaced by another 1)ase. It foll(jws that tliese salts can also be 



