48 HYPONITRITES ; PROPERTIES AND PREPAPvATION BY 



ver nitrate, dissolves silver liyponitrito to some extent, and in 

 other respects behaves like one of sodium hyponitrite. It has 

 not l)een obtained sufficiently undecomposed to be fit for quan- 

 titative analysis. 



Preparation of silver hyponitrite. 



The hyponitrites were discovered through tlie production 

 of the silver salt and since that discovery this hyponitrite has 

 been prepared and redescribed by many chemists. But no 

 deviation from the first account of it by myself occurs in the 

 later descriptions that is correct, while the only additions made 

 to it are that the salt can of course be obtained in a purer 

 state than I at first got it and that it gives when heated some 

 nitric peroxide. The very poor success in getting it in satisfactory 

 quantity in recent years is remarkable (see p. 35). It has been 

 due to erroneous procedure, partly in reducing the nitrite and 

 partly in converting the sodium hyponitrite into the silver salt. 



The concentrated solution of sodium hyponitrite and hydr- 

 oxide, already described (p. 38), is to be mixed with just sufficient 

 silver sulphate or silver nitrate, in presence of much water, for 

 the sodium hydroxide is not to be neutralised but only to be 

 largely diluted. (Neutralisation can, indeed,' precede precipita- 

 tion, if desired, as in preparing mercury and other hyponitrites, 

 but it is here quite unnecessary and risks the loss of some 

 hyponitrite). Silver sulphate is to be used as the precipitant 

 where it is essential to exclude nitrate from the silver hyponi- 

 trite ; for, as will be shown, washing and reprecipitating are 

 usually imperfect means of purifying the precipitate. 



Supposing a half gram molecule of sodium nitrite to have 



