Copper, Neu′tral Acetate of. Cu(C2H3O2)2. Syn. Nor′mal cupric acetate, Acetate of copper, Crys′tallised ver′digris. Prep. Dissolve common verdigris or cupric hydrate in hot acetic acid, so as to form a highly concentrated solution; filter and place in a cool situation to crystallise.
Prop. Beautiful dark, bluish-green prisms, which dissolve in 14 parts of cold and 5 parts of boiling water.
Copper, Ba′sic Acetates of. Syn. Ba′sic cu′pric acetates, Sub-ac′etates of copper. Common verdigris is a mixture of several basic acetates which have a green or blue colour. One of these (SESQUIBASIC ACETATE) is obtained by digesting powdered verdigris in tepid water, filtering, and leaving the soluble part to spontaneous evaporation. It may also be obtained in a state of purity by adding liquor of ammonia in small portions to a boiling concentrated solution of the neutral acetate till the precipitate is just redissolved, and leaving the solution to cool. It forms a blue, crystalline mass, but little soluble in cold water. The green, insoluble residue of the verdigris, after treatment with tepid water, contains another acetate (TRIBASIC ACETATE); this may be formed by digesting neutral acetate of copper with the hydrated oxide. A third salt (DIBASIC ACETATE, BLUE VERDIGRIS) is prepared on a large scale in France by exposing copper to the air in contact with fermenting wine-lees.
Copper, Ammo′′nio-sul′phate of. Syn. Sulphate of cuprammonium. Cu′pro-sulphate of ammo′′nia; Cu′pri ammo′′nio-sulphas, L.; Cuivre ammoniacal, Fr.; Kupfer salmiak, Ger. Prep. Sulphate of copper, 1 oz.; sesquicarbonate of ammonium, 11⁄2 oz.; rub together until carbonic acid ceases to be evolved, then wrap it in bibulous paper, and dry it in the air.
Pur. Pulverulent; dark blue; at an intense heat it is changed into oxide of copper, at first sesquicarbonate of ammonia, and, afterwards,
sulphate of ammonia, being thrown off. It is soluble in water to a splendid purple-blue solution, from which the salt is precipitated by alcohol in blue crystals. This solution has the peculiar property of dissolving CELLULOSE (cotton, paper, &c.). The cellulose may be precipitated from the solution in colourless flakes by the addition of acids.
Uses., &c. It is occasionally employed in pyrotechny. In medicine, it has been given in chorea, epilepsy, hysteria, &c., but is now principally used as an injection, as a wash for foul ulcers, used as a collyrium, in opacity of the cornea.—Dose, 1⁄4 gr., gradually increased to 5 gr., twice a day. Great care must be taken in drying, as it is apt not only to lose a large portion of its weight, but to become of an inferior colour. Both the ingredients should be separately reduced to powder before mixing them.
Copper, Ar′senite of. Cu(AsO2)2. See Green Pigments (Scheele’s Green).
Copper, Carbonate of. CuCO3. Syn. Diba′sic carbonate of copper, Dicarbonate of c.; Cupri carbonas, L. Prep. Add carbonate of soda in excess to a solution of sulphate of copper, and warm the mixture till the pale-blue, flocculent precipitate becomes sandy and assumes a green tint. Used as a pigment. See Green Pigments and Verditer.
Obs. As prepared above, the carbonate contains 2 equivalents of water. The beautiful green mineral, MAL′ACHITE, has a similar composition, but contains only 1 equiv. of water. Another carbonate (TRIBASIC C., BLUE C.), occurs as a natural ore in large, transparent crystals, of the most intense blue; it has not yet been artificially imitated.