280 Notices of the Labours of Continental Chemists. 



perature, only reduced copper occurs. When the green 

 powder is heated over a spirit-lamp, a beautiful combustion 

 appears before red heat; at the same time it is converted with 

 violent disengagement of nitrogen into metallic copper : this 

 indicates that the green powder is a combination of nitrogen 

 with copper, which is confirmed by numerous experiments. 

 The formation of the nitruret of copper takes place long be- 

 fore the boiling point of linseed oil, and, in fact, at 250° C, 

 while the reduction of the oxide of copper, by means of hy- 

 drogen, only takes place at the boiling point. The degree of 

 division of the oxide is of much importance, and it is best to 

 employ an oxide prepared by precipitating a hot solution of 

 the nitrate of copper with caustic potash, and boiling. Even 

 with this precaution it is difficult to prepare a nitruret of cop- 

 per perfectly free from oxide; for, after the action of am- 

 monia has continued for about eight hours, all formation of 

 water ceases ; the powder must then be well shaken, which 

 must be often repeated, and towards the end of the operation 

 triturated several times in a mortar. To produce twenty 

 grammes of nitruret of copper, it is requisite to continue the 

 action of ammonia during 120 hours. The hydrate or car- 

 bonate of copper cannot be employed with the same ad- 

 vantage as the oxide, as they become heated in contact with 

 ammonia, and the temperature rises so high that the nascent 

 nitruret is immediately decomposed. The nitruret of copper 

 is a somewhat blackish, fine powder (the green powder con- 

 tains still undecomposed oxide of copper), which, at a tempe- 

 rature of about 300°, becomes decomposed, whilst evolving a 

 beautiful red light, into copper and nitrogen, which is mixed 

 with nitric oxide, if the combination still contain some oxide. 

 In carbonic acid, and in ammoniacal gas, it is decomposed at 

 a higher, in oxygen, at a lower temperature, than in atmo- 

 spheric air. It is not decomposed by pressure or friction. 

 Acids decompose it; brought into contact with sulphuric acid, 

 a violent disengagement of nitrogen ensues, and the copper 

 remains behind in a metallic state. Acids which dissolve the 

 copper, as nitric acid, act far more violently. It is impossible 

 to free it entirely from adherent ammonia. The analysis was 

 made according to the method generally adopted for organic 

 nitrogenous substances. The amount of copper was deter- 

 mined by dissolving a portion of the combination in nitric 

 acid, and converting the nitrate into oxide of copper. The 

 results obtained agree exceedingly well with the formula 

 NCu 3 *. 



[* See Prof. Grove's [taper on some electro nitrogurets, in the present 

 volume, pp. 100, 103 : see also, Phil. Mag. Second Series, vol. iv. p. 155 j 

 vol. vi. p. 147. — Edit.] 



