SOÙIUM OR POTASSIUM : £i)\VAHD DlVEllS. 51 



silver oxide. If along with such impurity there is also black 

 silver suboxide, the colour becomes dull greyish yellow, but 

 when other impurities are absent, the presence of a little black 

 oxide renders it somewhat bright green, as seen principally in 

 the crude salt prepared by the oxyamidosulphonate method. 

 The difference of colour observed has even suggested the pos- 

 sibility of the existence of different modifications, but there is 

 really nothing to support the notion. 



Precipitated from strongly alkaline solution, or from con- 

 centrated solutions of the sodium salt and silver nitrate, or on 

 rubbing the calcium salt with strong solution of silver nitrate, 

 silver hyponitrite is dense ; but precipitated from its dilute acid 

 solution by neutralising, it is flocculent and bulky. When 

 deposited from its ammoniacal solution through evaporation or 

 large dilution with water it is crystalline (Kirschner ; but see 

 also Paal and Kretschmer). 



It is slightly more soluble in water than silver chloride, 

 soluble in well diluted nitric acid and sulphuric acid, so as to 

 be recoverable from its solution by quickly neutralising the acid. 

 The quantity of nitric acid required to dissolve it is consider- 

 able, being about 3 equivalents. The sulphuric acid solution very 

 soon deposits silver sulphate. Acetic acid dissolves it only very 

 slightly in the cold ; phosphoric acid dissolves it but not very 

 freely. It is dissolved by ammonia solution but only sparingly 

 when this is very dilute, and can be recovered either by neu- 

 tralising or dissipating the ammonia. It is also soluble in 

 ammonium carbonate solution and very slightly in ammonium 

 nitrate solution. Of particular interest is its solubility to a 

 slight extent in hyponitrous acid solution and to a greater 

 degree in solution of an alkali hyponitrite. 



