Nomenclature
CAS number: 1317-39-1
Red copper oxide; C.I. 77402; yellow cuprocide; Cacobre (Syngenta); Cooper-Sandoz (Syngenta).
Cu
2O; mol wt 143.09.
Cu 88.82%, O 11.18%.
Description and references
Occurs in nature as the mineral cuprite (red to reddish-brown octahedral or cubic crystals). Prepd
commercially by furnace reduction of mixtures of copper oxides with
Cu: Drapeau, Johnson, US 2758014; US 2891842 (1956, 1959 both to Glidden); by decompn of copper ammonium carbonate: Rowe, US 2474497; Klein, US 2474533 (both 1949 to Lake Chemical); Rowe, US 2536096; Munn, US 2670273 (1951, 1954 both to Mountain Copper); by treatment of Cu(OH)2 with SO2:
Rowe, US 2665192 (1954 to Mountain Chemical); or by electrolysis of an aq
soln of NaCl between Cu electrodes: Arend, Paint Technol. 13, 265 (1948). Laboratory
prepns: Glemser, Sauer in Handbook of Preparative
Inorganic Chemistry vol. 2, G. Brauer, Ed.
(Academic Press, New York, 2nd ed., 1965) p 1011. Toxicity study:
H. F. Smyth et al., Am. Ind. Hyg.
Assoc. J. 30, 470 (1969).
Properties
Cubic crystals or microcrystalline powder. Color
may be yellow, red, or brown depending on the method of prepn and
the particle size. Stable in dry air; gradually oxidizes in moist
air to CuO. mp 1232°; d425 6.0. Practically insol in water. Sol in NH4OH; in HCl
forming CuCl which dissolves in excess HCl. With dil H2SO4 or dil HNO3, the cupric salt is formed
and half the copper is pptd as the metal. LD50 orally in rats: 0.47 g/kg (Smyth).Use
Fungicide; antiseptic for fishnets; in antifouling
paints for marine use; in photoelectric cells; as red pigment for
glass, ceramic glazes; in brazing pastes; in rectifiers; as catalyst.