Cuprous Oxide

Title: Cuprous Oxide
CAS Registry Number: 1317-39-1
Additional Names: Red copper oxide; C.I. 77402; yellow cuprocide
Trademarks: Cacobre (Syngenta); Cooper-Sandoz (Syngenta)
Molecular Formula: Cu2O
Molecular Weight: 143.09
Percent Composition: Cu 88.82%, O 11.18%
Literature 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).
Melting point: mp 1232°
Density: d425 6.0
Toxicity data: 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.
Cuprous Potassium Cyanide Cuprous Selenide Cuprous Sulfide Cuprous Sulfite Cuprous Thiocyanate

Copper(I) oxide
Copper(I) oxide
Copper(I) oxide unit cell
CAS number 1317-39-1 YesY
PubChem 10313194
ChemSpider 8488659 YesY
EC number 215-270-7
KEGG C18714 YesY
RTECS number GL8050000
Jmol-3D images Image 1
Image 2
Molecular formula Cu2O
Molar mass 143.09 g/mol
Appearance brownish-red solid
Density 6.0 g/cm3
Melting point 1,232 °C; 2,250 °F; 1,505 K
Boiling point 1,800 °C; 3,270 °F; 2,070 K
Solubility in water Insoluble
Solubility in acid Soluble
Band gap 2.137 eV
Crystal structure cubic
Std molar
entropy So298
93 J·mol−1·K−1
Std enthalpy of
formation ΔfHo298
−170 kJ·mol−1
EU Index 029-002-00-X
EU classification Harmful (Xn)
Dangerous for the environment (N)
R-phrases R22, R50/53
S-phrases (S2), S22, S60, S61
NFPA 704
NFPA 704.svg
Related compounds
Other anions Copper(I) sulfide
Copper(II) sulfide
Copper(I) selenide
Other cations Copper(II) oxide
Silver(I) oxide
Nickel(II) oxide
Zinc oxide
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Copper(I) oxide or cuprous oxide is the inorganic compound with the formula Cu2O. It is one of the principal oxides of copper. This red-coloured solid is a component of some antifouling paints. The compound can appear either yellow or red, depending on the size of the particles.[1] Copper(I) oxide is found as the reddish mineral cuprite.