308 ■fMl'igmce an^^MiUeUme&m'^ArUd^s. 



The author concluded that the decompbsitiort of ferridcytinide into 

 ferrocyanide, would afford cyanogen which would act as if it were 

 free ; and he found that when he heated oxide of lead in a mixture 

 of ferrideyanide and potash, he procured binoxide of lead, and the 

 solution contained ferrocyanide of potassium only. Ha^dng thus 

 proved that the ferrideyanide might be substituted for cyanogen aft 

 an oxidizing agent, experiments were performed on the superoxi- 

 dizement of various oxides. — Journ. dePharm. et de CA., Juin 1845. 



miilunqimii s i&:1u(i ,boouboH\ kl J!i')1ii) on noidtjiloa i}{fJ0 jj tii vMa 



SUPEROXIDIZEMENT OF METALLIC OXIDES 'l^YMfiANS OF T&jk 

 FERRIDCYANiDE OF POTASSIUM. BY M. BOUDAULT. , ' ', 



The author remarks, that metallic oxidjes/ in' gdneitalrlliave ai ten- 

 dency to pass to a higher degree of oxidizemerit ; and some of them 

 undergo it with great readiness, under the oxidizing influence of 

 cyanogen, either at common temperatures or when boiling, accoud*- 

 ing as the oxide is more or less superoxidizable. ' : 's!'! 



Oxide of Manganese. — When protoxide of manganese, which has 

 been precipitated without the contact of air, or a salt containing this 

 oxide, is added to a mixed solution of cold ferrideyanide of potas- 

 sium and potash, there are immediately obtained peroxide of man- 

 ganese and ferrocyanide of potassium : with a large quantity of pot- 

 ash, crystallized peroxide of manganese was formed. If; instead of 

 adding an excess of ferrideyanide, an excess of a salt of manganese 

 be employed with a large quantity of potash, a reddish-brown pre- 

 cipitate may be obtained, which is probably the manganoso-man- 

 ganic oxide. 



Oxide of Nickel and Oxide of Cobalt. — The protoxide of nickel, 

 when added to an alkaline solution of the red salt, does not appear 

 to be superoxidized ; and if it be boiled for some time decomposition 

 occurs unconnected with oxidizement. 



The same is the case with oxide of cobalt ; there occurs, never- 

 theless, a moment in which the oxide of cobalt seems to be super- 

 oxidized, but it is probably reduced by the ferrocyanide which is 

 formed. 



Oxide of Lead. — The superoxidation of lead is the most marked 

 of any oxide ; a salt of oxide of lead, or the oxide itself, when dis- 

 solved in potash, is converted into binoxide, and almost always preci- 

 pitated in the crystalline state ; this latter fact, however, ajipears to 

 depend upon the quantity of potash employed. On some occasions 

 the author obtained minium by employing excess of the salt of lead, 

 and heating the liquor but slightly. 



Oxide of Copper. — The ferrideyanide of copper, or the oxide, are 

 superoxidized by the mixed solution of ferrideyanide of potassium 

 and potash ; there are obtained a black precipitate, and ferrocyanide 

 as usual. 



Oxide of Tin. — The salts of protoxide of tin effect a reduction of 

 the ferrideyanide, which indicates superoxidizement ; but the author 

 could not ascertain the nature of the oxide which is precipitated. 



