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Copper(II) oxide

|Section2={{Chembox Properties | Formula = CuO | MolarMass = 79.545 g/mol | Appearance = black to brown powder | Density = 6.315 g/cm3 | MeltingPtC = 1326 | BoilingPtC = 2000 | Solubility = insoluble | SolubleOther = soluble in ammonium chloride, potassium cyanide insoluble in alcohol, ammonium hydroxide, ammonium carbonate | BandGap = 1.2  eV | pKa = | pKb = | RefractIndex = 2.63 | MagSus = +238.9·10−6 cm3/mol }} |Section3={{Chembox Structure | CrystalStruct = monoclinic, mS8The effect of hydrostatic pressure on the ambient temperature structure of CuO, Forsyth J.B., Hull S., J. Phys.: Condens. Matter 3 (1991) 5257-5261 , . 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°. | SpaceGroup = C2/c, #15 | LattConst_a = 4.6837 | LattConst_b = 3.4226 | LattConst_c = 5.1288 | LattConst_beta = 99.54 | Coordination = }} |Section4={{Chembox Thermochemistry | DeltaHf = −156 kJ·mol−1 | Entropy = 43 J·mol−1·K−1 }} |Section7={{Chembox Hazards | ExternalSDS = Fischer Scientific | EUClass = Harmful (Xn) Dangerous for the environment (N) | MainHazards = | NFPA-H = 2 | NFPA-F = 0 | NFPA-R = 1 | NFPA-S = | RPhrases = | SPhrases = | FlashPt = Non-flammable | PEL = TWA 1 mg/m3 (as Cu) | REL = TWA 1 mg/m3 (as Cu) | IDLH = TWA 100 mg/m3 (as Cu) }} |Section8={{Chembox Related | OtherAnions = Copper(II) sulfide | OtherCations = Nickel(II) oxide Zinc oxide | OtherFunction = | OtherFunction_label = | OtherCompounds = Copper(I) oxide }} }} 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 or cuprous oxide. As a mineral, it is known as tenorite. It is a product of copper mining and the precursor to many other copper-containing products and chemical compounds.H. Wayne Richardson "Copper Compounds'' in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim.

Production

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 For laboratory uses, pure copper(II) oxide is better prepared by heating copper(II) nitrate, copper(II) hydroxide or copper(II) carbonate: 2 Cu(NO3)2 → 2 CuO + 4 NO2 + O2 Cu(OH)2 (s) → CuO (s) + H2O (l) CuCO3 → CuO + CO2

Reactions

Copper(II) oxide is an amphoteric oxide, so it dissolves in mineral acids such as hydrochloric acid, sulfuric acid or nitric acid to give the corresponding copper(II) salts: 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 It can also be reduced to copper metal using hydrogen, carbon monoxide, or carbon: 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 belongs to the monoclinic crystal system. The copper atom is coordinated by 4 oxygen atoms in an approximately square planar configuration. The work function of bulk CuO is 5.3 eV 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.

Uses

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 incorrectly used as a dietary supplement in animal feed. Due to low bioactivity, negligible copper is absorbed. Cupric Oxide Should Not Be Used As a Copper Supplement for Either Animals or Humans, Baker, D. H., J. Nutr. 129, 12 (1999) 2278-2279 It is also used when welding with copper alloys.

Use in disposal

Cupric oxide can be used to safely dispose of hazardous materials such as cyanide, hydrocarbons, halogenated hydrocarbons and dioxins, through oxidation.{{Cite web | last = Kenney | first = Charlie W. | last2 = Uchida | first2 = Laura A. | title = Use of copper (II) oxide as source of oxygen for oxidation reactions | date = April 1986 | url = http://www.freepatentsonline.com/4582613.html | accessdate = 2007-06-29 | postscript = }} The decomposition reactions of phenol and pentachlorophenol follow these pathways: C6H5OH + 14CuO → 6CO2 + 3H2O + 14Cu C6Cl5OH + 2H2O + 9CuO → 6CO2 + 5HCl + 9Cu

See also

References

External links

"green air" © 2007 - Ingo Malchow, Webdesign Neustrelitz
This article based upon the http://en.wikipedia.org/wiki/Copper(II)_oxide, the free encyclopaedia Wikipedia and is licensed under the GNU Free Documentation License.
Further informations available on the list of authors and history: http://en.wikipedia.org/w/index.php?title=Copper(II)_oxide&action=history
presented by: Ingo Malchow, Mirower Bogen 22, 17235 Neustrelitz, Germany