|Molar mass||79.545 g/mol|
|Appearance||black to brown powder|
|Melting point||1,326 °C (2,419 °F; 1,599 K)|
|Boiling point||2,000 °C (3,630 °F; 2,270 K)|
|Solubility||soluble in ammonium chloride, potassium cyanide
insoluble in alcohol, ammonium hydroxide, ammonium carbonate
|Band gap||1.2 eV|
Refractive index (nD)
a = 4.6837, b = 3.4226, c = 5.1288
α = 90°, β = 99.54°, γ = 90°
Std enthalpy of
|Safety data sheet||Fischer Scientific|
|EU classification||Harmful (Xn)
Dangerous for the environment (N)
|US health exposure limits (NIOSH):|
|TWA 0.1 mg/m3|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|what is: / ?)(|
Copper(II) oxide or cupric oxide is the inorganic compound with the formula CuO. A black solid, it is one of the two stable oxides of copper, the other being Cu2O. As a mineral, it is known as tenorite and paramelaconite. It is a product of copper mining and the precursor to many other copper-containing products and chemical compounds.
It is produced on a large scale by pyrometallurgy used to extract copper from ores. The ores are treated with an aqueous mixture of ammonium carbonate, ammonia, and oxygen to give copper(I) and copper(II) ammine complexes, which are extracted from the solids. These complexes are decomposed with steam to give CuO.
It can be formed by heating copper in air at around 300 - 800°C:
- 2 Cu + O2 → 2 CuO
- 2 Cu(NO3)2 → 2 CuO + 4 NO2 + O2
- Cu(OH)2 (s) → CuO (s) + H2O (l)
- CuCO3 → CuO + CO2
- CuO + 2 HNO3 → Cu(NO3)2 + H2O
- CuO + 2 HCl → CuCl2 + H2O
- CuO + H2SO4 → CuSO4 + H2O
It reacts with concentrated alkali to form the corresponding cuprate salts:
- 2 MOH + CuO + H2O → M2[Cu(OH)4]
- CuO + H2 → Cu + H2O
- CuO + CO → Cu + CO2
- 2CuO + C → 2Cu + CO2
When cupric oxide is substituted for iron oxide in thermite the resulting mixture is a low explosive, not an incendiary.
Structure and physical properties
Copper(II) oxide is a p-type semiconductor, with a narrow band gap of 1.2 eV. Cupric oxide can be used to produce dry cell batteries. It could also been used in wet cell batteries as the cathode, with lithium as an anode, and dioxalane mixed with lithium perchlorate as the electrolyte.
As a significant product of copper mining, copper(II) oxide is the starting point for the production of other copper salts. For example, many wood preservatives are produced from copper oxide.
Cupric oxide is used as a pigment in ceramics to produce blue, red, and green, and sometimes gray, pink, or black glazes.
It is also used as a dietary supplement in animals.
Use in disposal
The decomposition of phenol and pentachlorophenol follow these pathways:
- C6H5OH + 14CuO → 6CO2 + 3H2O + 14Cu
- C6Cl5OH + 2H2O + 9CuO → 6CO2 + 5HCl + 9Cu
- The effect of hydrostatic pressure on the ambient temperature structure of CuO, Forsyth J.B., Hull S., J. Phys.: Condens. Matter 3 (1991) 5257-5261 , doi:10.1088/0953-8984/3/28/001. Crystallographic point group: 2/m or C2h. Space group: C2/c. Lattice parameters: a = 4.6837(5), b = 3.4226(5), c = 5.1288(6), α = 90°, β = 99.54(1)°, γ = 90°.
- "NIOSH Pocket Guide to Chemical Hazards #0151". National Institute for Occupational Safety and Health (NIOSH).
- H. Wayne Richardson "Copper Compounds in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. doi:10.1002/14356007.a07_567
- F. P. Koffyberg and F. A. Benko (1982). "A photoelectrochemical determination of the position of the conduction and valence band edges of p-type CuO". J. Appl. Phys. 53 (2): 1173. doi:10.1063/1.330567.
- "Uses of Copper Compounds: Other Copper Compounds". Copper Development Association. 2007. Retrieved 2007-01-27.
- "Cupric Oxide Data Sheet". Hummel Croton Inc. 2006-04-21. Retrieved 2007-02-01.
- Kenney, Charlie W.; Uchida, Laura A. (April 1986). "Use of copper (II) oxide as source of oxygen for oxidation reactions". Retrieved 2007-06-29.
|Wikimedia Commons has media related to Copper(II) oxide.|
- National Pollutant Inventory - Copper and compounds fact sheet
- Copper oxides project page
- CDC - NIOSH Pocket Guide to Chemical Hazards