Copper(II) hydroxide

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Copper(II) hydroxide
Copper(II) hydroxide
Kristallstruktur Kupfer(II)-hydroxid.png
Names
IUPAC name
Copper(II) hydroxide
Other names
Cupric hydroxide
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.039.817
KEGG
UNII
Properties
Cu(OH)2
Molar mass 97.561 g/mol
Appearance Blue or blue-green solid
Density 3.368 g/cm3, solid
Melting point 80 °C (176 °F; 353 K) (decomposes into CuO)
negligible
2.20 x 10−20[1]
Solubility insoluble in ethanol;
soluble in NH4OH, KCN
+1170.0·10−6 cm3/mol
Thermochemistry
108 J·mol−1·K−1
−450 kJ·mol−1
Hazards
Main hazards Skin, Eye, & Respiratory Irritant
Safety data sheet http://www.sciencelab.com/xMSDS-Cupric_Hydroxide-9923594
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 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point Non-flammable
Lethal dose or concentration (LD, LC):
1000 mg/kg (oral, rat)
US health exposure limits (NIOSH):
PEL (Permissible)
TWA 1 mg/m3 (as Cu)[2]
REL (Recommended)
TWA 1 mg/m3 (as Cu)[2]
IDLH (Immediate danger)
TWA 100 mg/m3 (as Cu)[2]
Related compounds
Other anions
Copper(II) oxide
Copper(II) carbonate
Copper(II) sulfate
Copper(II) chloride
Other cations
Nickel(II) hydroxide
Zinc hydroxide
Iron(II) hydroxide
Cobalt hydroxide
Related compounds
Copper(I) oxide
Copper(I) chloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Copper(II) hydroxide is the hydroxide of the copper with the chemical formula of Cu(OH)2. It is a pale blue solid. Some forms of copper(II) hydroxide are sold as "stabilized" copper hydroxide, although they likely consist of a mixture of copper(II) carbonate and hydroxide. Copper hydroxide is a weak base.

Occurrence[edit]

Copper(II) hydroxide has been known since copper smelting began around 5000 BC although the alchemists were probably the first to manufacture it by mixing solutions of lye (sodium or potassium hydroxide) and blue vitriol (copper(II) sulfate).[3] Sources of both compounds available in antiquity.

It was produced on an industrial scale during the 17th and 18th centuries for use in pigments such as blue verditer and Bremen green.[4] These pigments were used in ceramics and painting.[5]

Laboratory synthesis[edit]

Copper(II) hydroxide can be produced by adding a sodium hydroxide to a dilute solution of copper(II) sulfate (CuSO4·5H2O).[6] The precipitate produced in this manner, however, often contains water and an appreciable amount of sodium hydroxide impurity. A purer product can be attained if ammonium chloride is added to the solution beforehand.[7] Alternatively, copper hydroxide is readily made by electrolysis of water (containing a little electrolyte such as sodium sulfate, or magnesium sulfate). A copper anode is used, often made from scrap copper.

Mineral[edit]

The mineral of the formula Cu(OH)2 is called spertiniite. Copper(II) hydroxide is rarely found as an uncombined mineral because it slowly reacts with carbon dioxide orm a basic copper(II) carbonate. Thuaction:

2 Cu + H2O + CO2 + O2 → Cu(OH)2 + CuCO3

The green material is in principle a 1:1 mole mixture of Cu(OH)2 and CuCO3.[8] This patina forms on bronze and other copper alloy statues such as the Statue of Liberty.

Structure[edit]

The structure of Cu(OH)2 has been determined by X-ray crystallography The copper center is square pyramidal. Four Cu-O distances in the plane range are 1.96 Å, and the axial Cu-O distance is 2.36 Å. The hydroxide ligands in the plane are either doubly bridging or triply bridging.[9]

Reactions[edit]

It is stable to about 100 °C.[6]

Copper(II) hydroxide reacts with a solution of ammonia to form a deep blue solution of tetramminecopper [Cu(NH3)4]2+ complex ion. It catalyzes the oxidation of ammonia solutions in presence of dioxygen, giving rise to copper ammine nitrites, such as Cu(NO2)2( NH3)n.[10][11]

Copper(II) hydroxide is mildly amphoteric. It dissolves slightly in concentrated alkali, forming [Cu(OH)4]2−.[12][6]

Reagent for organic chemistry[edit]

Copper(II) hydroxide has a rather specialized role in organic synthesis. Often, when it is utilized for this purpose, it is prepared in situ by mixing a soluble copper(II) salt and potassium hydroxide.

It is sometimes used in the synthesis of aryl amines. For example, copper(II) hydroxide catalyzes the reaction of ethylenediamine with 1-bromoanthraquinone or 1-amino-4-bromoanthraquinone to form 1-((2-aminoethyl)amino)anthraquinone or 1-amino-4-((2-aminoethyl)amino)anthraquinone, respectively:[13]

UllmannCu(OH)2.PNG

Copper(II) hydroxide also converts acid hydrazides to carboxylic acids at room temperature. This conversion is useful in the synthesis of carboxylic acids in the presence of other fragile functional groups. The yields are generally excellent as is the case with the production of benzoic acid and octanoic acid:[13]

Cu(OH)2 CarboxylicAcidCatalyst.PNG

Uses[edit]

Copper(II) hydroxide in ammonia solution, known as Schweizer's reagent, possesses the interesting ability to dissolve cellulose. This property led to it being used in the production of rayon, a cellulose fiber.

It is also used widely in the aquarium industry for its ability to destroy external parasites in fish, including flukes, marine ich, brook and marine velvet, without killing the fish. Although other water-soluble copper compounds can be effective in this role, they generally result in high fish mortality.

Copper(II) hydroxide has been used as an alternative to the Bordeaux mixture, a fungicide and nematicide.[14] Such products include Kocide 3000, produced by Kocide L.L.C. Copper(II) hydroxide is also occasionally used as ceramic colorant.

Copper(II) hydroxide has been combined with latex paint, making a product designed to control root growth in potted plants. Secondary and lateral roots thrive and expand, resulting in a dense and healthy root system. It was sold under the name Spin Out, which was first introduced by Griffin L.L.C. The rights are now owned by SePRO Corp.[15] It is now sold as Microkote either in a solution you apply yourself, or as treated pots.

Other copper(II) hydroxides[edit]

Chemical structure of azurite, one of many copper(II) hydroxides (color code: red = O, green = Cu, gray = C, white = H).[16]

Together with other components, copper(II) hydroxides are numerous. Several copper(II)-containing minerals contain hydroxide. Notable examples include azurite, malachite, antlerite, and brochantite. Azurite (2CuCO3·Cu(OH)2) and malachite (CuCO3·Cu(OH)2) are hydroxy-carbonates, whereas antlerite (CuSO4·2Cu(OH)2) and brochantite (CuSO4·3Cu(OH)2) are hydroxy-sulfates.

Many synthetic copper(II) hydroxide derivatives have been investigated.[17]

References[edit]

  1. ^ Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0-07-049439-8
  2. ^ a b c "NIOSH Pocket Guide to Chemical Hazards #0150". National Institute for Occupational Safety and Health (NIOSH). 
  3. ^ Richard Cowen, Essays on Geology, History, and People, Chapter 3: "Fire and Metals: Copper".
  4. ^ Tony Johansen, Historic Artist's Pigments. PaintMaking.com. 2006.
  5. ^ Blue verditer Archived 2007-09-27 at the Wayback Machine.. Natural Pigments. 2007.
  6. ^ a b c O. Glemser and H. Sauer "Copper(II) Hydroxide" in Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 1. p. 1013.
  7. ^ Y. Cudennec, A. Lecerf (2003). "The transformation of Cu(OH)2 into CuO, revisited". Solid State Sciences. 5: 1471–1474. doi:10.1016/j.solidstatesciences.2003.09.009. 
  8. ^ Masterson, W. L., & Hurley, C. N. (2004). Chemistry: Principles and Reactions, 5th Ed. Thomson Learning, Inc. (p 331)"
  9. ^ H. R. Oswald, A. Reller, H. W. Schmalle, E. Dubler (1990). "Structure of Copper(II) Hydroxide, Cu(OH)2". Acta Cryst. C46: 2279–2284. doi:10.1107/S0108270190006230. 
  10. ^ Y. Cudennec; et al. (1995). "Etude cinétique de l'oxydation de l'ammoniac en présence d'ions cuivriques". Comptes Rendus Académie Sciences Paris, série II, Méca; phys. chim. astron. 320 (6): 309–316. 
  11. ^ Y. Cudennec; et al. (1993). "Synthesis and study of Cu(NO2)2(NH3)4 and Cu(NO2)2(NH3)2". European journal of solid state and inorganic chemistry. 30 (1-2): 77–85. 
  12. ^ Pauling, Linus (1970). General Chemistry. Dover Publications, Inc. (p 702).
  13. ^ a b Tsuda, T. (2001). "Copper(II) Hydroxide". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rc228. 
  14. ^ Bordeaux Mixture. UC IPM online. 2007.
  15. ^ "SePRO Corporation".
  16. ^ Zigan, F.; Schuster, H.D. (1972). "Verfeinerung der Struktur von Azurit, Cu3(OH)2(CO3)2, durch Neutronenbeugung". Zeitschrift fuer Kristallographie, Kristallgeometrie, Kristallphysik, Kristallchemie. 135: 416–436. 
  17. ^ Kondinski, A.; Monakhov, K. (2017). "Breaking the Gordian Knot in the Structural Chemistry of Polyoxometalates: Copper(II)–Oxo/Hydroxo Clusters". Chemistry, Eur. Journal. doi:10.1002/chem.201605876. 

External links[edit]