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Cuprous oxide

Copper(I) oxide
Copper(I) oxide
Copper(I) oxide unit cell
Copper(I)-oxide-3D-balls.png
Names
IUPAC name
Copper(I) oxide
Other names
Cuprous oxide
Dicopper oxide
Cuprite
Red copper oxide
Identifiers
3D model (Jmol)
ChemSpider
ECHA InfoCard 100.013.883
EC Number 215-270-7
KEGG
PubChem CID
RTECS number GL8050000
UNII
Properties
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)
Insoluble
Solubility in acid Soluble
Band gap 2.137 eV
-20·10−6 cm3/mol
Structure
cubic
Thermochemistry
93 J·mol−1·K−1
−170 kJ·mol−1
Hazards
Safety data sheet SIRI.org
Harmful (Xn)
Dangerous for the environment (N)
R-phrases R22, R50/53
S-phrases (S2), S22, S60, S61
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g., calcium Special hazards (white): no codeNFPA 704 four-colored diamond
US health exposure limits (NIOSH):
PEL (Permissible)
TWA 1 mg/m3 (as Cu)
REL (Recommended)
TWA 1 mg/m3 (as Cu)
IDLH (Immediate danger)
TWA 100 mg/m3 (as Cu)
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
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
YesY  (what is YesYN ?)
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, the other being CuO or cupric oxide. 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. Copper(I) oxide is found as the reddish mineral cuprite.

Copper(I) oxide may be produced by several methods. Most straightforwardly, it arises via the oxidation of copper metal:

Additives such as water and acids affect the rate of this process as well as the further oxidation to copper(II) oxides. It is also produced commercially by reduction of copper(II) solutions with sulfur dioxide. Aqueous cuprous chloride solutions react with base to give the same material. In all cases, the color is highly sensitive to the procedural details.

Formation of copper(I) oxide is the basis of the Fehling's test and Benedict's test for reducing sugars. These sugars reduce an alkaline solution of a copper(II) salt, giving a bright red precipitate of Cu2O.

It forms on silver-plated copper parts exposed to moisture when the silver layer is porous or damaged. This kind of corrosion is known as red plague.

Little evidence exists for cuprous hydroxide, which is expected to rapidly undergo dehydration. A similar situation applies to the hydroxides of gold(I) and silver(I).

The solid is diamagnetic. In terms of their coordination spheres, copper centres are 2-coordinated and the oxides are tetrahedral. The structure thus resembles in some sense the main polymorphs of SiO2, and both structures feature interpenetrated lattices.


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