Cupric Oxide

CuO. Syn. Ox′ide of copper , Black oxide , Protoxide ; Cu′pri protox′ydum . Prep. By heating the nitrate or carbonate of copper to redne . When it ceases to lose weight the conversion is completed, and the oxide appears as a heavy, black powder. By heating in the air the hydrated oxide thrown down from solutions of copper by pure pota a. By adding caustic pota a, in exce , to a solution of a cupric salt, and heating the whole to a boiling-point; the precipitate is then collected, washed, and dried. A heavy, dark-brown powder. Uses, . Protoxide of copper is unchanged by heat unle combustible matter is present, when it readily parts with its oxygen; hence its general use in ORGANIC ANALYSIS as a source of that element. It communicates a beautiful green colour to gla and enamels. With the acids it produces the ordinary salts of copper.