Cobaltous into Cobaltic Nibrite. 3 



and in other similar ways from what is known of cobaltic and 

 other allied compounds, these constituent salts may have their 

 formulae expanded into the following, as probably accurate expres- 

 sions of their constitution : 



/OH 



Co",Co"; (NO.,)i„(OH)^ = (NO.,Co"NO., NO.,)« = Co";--(OH OHCo"NO.,), 



\0H 



/(OH OH Co" OH) 



Co"6Co"',(NO.Oio(OH)3 = (NO.Co"NO., NO.,)3=Co"'.,— (OH OH Co" NO,). 



\(0H OH Co" OH) 



It is unnecessary to add to these formulée the complex one for 

 the crystalline salt as compounded of them. The apposition in them 

 of NO2 with NO2 and of OK with OH serves to express, without 

 pretending to explain, the pairing of acidic components so char- 

 acteristic of such double salts as nitrites and cyanides. The NO2 

 and OH groups next on either side to the Co "2 group represent, 

 together with it, hemihydroxycobaltic nitrite, (N02)3Co'"2(OH)3, 

 existent probably, only in combination as a double nitrite. 

 Cobaltous nitrite and hydroxynitrite are similarly displayed in 

 these formulae. 



The self- conversion of cobaltous nitrite into cobaltic nitrite, 

 merely, would be shown by the equation, 



Co"(N02)2 + H.0= Co"'(N02)(OH)2 + NO, 



did all the cobalt nitrite ever become cobaltic, instead of but little 

 more than one-third of it. As, however, the whole of the cobalt 

 nitrite undoubtedly takes part in the change, this fact must be 

 presented in the equation framed to express the conversion. This 

 equation Avill be more readily followed by prefacing it with another, 

 showing part of the change : 



3 Co"(NOA + 2H,0= Co" (NO,)s(OH)„ Co"(N02)(OH) + 2 NO, 



