Manchester Memoirs, Vol. xlvii. (1903), No. \% 3 



confirmed Bayley's conclusions with regard to the oxide 

 C03O5, which I have obtained by adding an alkali, and 

 afterwards bromine in excess, to a solution of cobalt. If, 

 however, the bromine is added first, and then the alkali, 

 the oxide is always slightly lower than CogOs. 



Numerous other experimenters have described various 

 oxides of cobalt, some apparently very complicated. 

 Thus, Carnot* obtained two oxides by precipitation 

 with sodium hypochlorite and with bromine and alkali 

 respectively, which have the composition represented 

 pretty closely by the formulae CobOs and CogOig, — both 

 slightly lower than CogOs. 



Schroderf obtained the same results as Bayley, — that 

 is, C03O5, in the cold, and other oxides between that and 

 C02O3 on boiling, or when, as I have also noted, the cobalt 

 solution is treated with bromine first and then with alkali. 



Vortmann,j adding an alkali and solution of iodine to 

 cobalt sulphate, obtained oxides varying from a little 

 above CogOs to almost CoO,. 



F. Mawrow,§ by the action of potassium persulphate 

 on cobalt solutions, obtained C03O4, but in presence of 

 alkali Co„0.. 



E. Hiittnerll also obtained Co,0.j by the action of a 

 persulphate in presence of alkali. With sodium hypo- 

 chlorite he obtained Co,„Oi9, approximately. Cobalt sul- 

 phate with alkali and excess of iodine gave the oxide 

 CoO,,. According to both Vortmann and Hiittner iodine, 

 in presence of alkali, appears to give the highest oxide. 



McConnell and HaneslF describe the formation, by 



* Coiiipt. Keiid., T. 108, p. 610-12. 



t Chein. Centr., i8go, I., 931. 



X Ber. Dent. Cheiii. Ges., Bd. 24, p. 2744. 



§ Zeils. anorg. Chein., Bd. 24, 1900, p. 263. 



II Zeits. aiiofg. Chein., Bd. 27, 1901, p. 81. 



'^ [ourn. Chein. Soc, Vol. 71, 1897, p. 584. 



