Copper(II) hydroxide 2722147 221174006 2008-06-23T10:41:48Z William Avery 1398 Remove link to dab page [[Antiquity]] using [[:en:Wikipedia:Tools/Navigation_popups|popups]] assuming it means the times indefinitely long ago when alchemists worked {{Chembox new | Name = Copper(II) hydroxide | ImageFile = Copper(II) hydroxide.JPG <!-- | ImageSize = 200px --> | ImageName = Copper(II) hydroxide | IUPACName = Copper(II) hydroxide | OtherNames = Cupric hydroxide | Section1 = {{Chembox Identifiers | CASNo = 20427-59-2 }} | Section2 = {{Chembox Properties | Formula = [[Copper|Cu]][[Hydroxide|(OH)<sub>2</sub>]] | MolarMass = 97.561 g/mol | Appearance = Blue or blue-green solid | Density = 3.37 g/cm<sup>3</sup>, solid | Solubility = insoluble | Solvent = [[ethanol]] | SolubleOther = insoluble | MeltingPt = n/a, decomposes into CuO | BoilingPt = }} | Section7 = {{Chembox Hazards | ExternalMSDS = | MainHazards = Skin, Eye, & Respiratory Irritant | NFPA-H = 2 | NFPA-F = | NFPA-R = | FlashPt = Non-flammable | RPhrases = R36 R37 R38 | SPhrases = S26 }} | Section8 = {{Chembox Related | OtherAnions = [[Copper(II) sulfate|CuSO<sub>4</sub>]], [[Copper(II) chloride|CuCl<sub>2</sub>]], [[Copper(II) oxide|CuO]],<br /> [[Copper(II) nitrate|Cu(NO<sub>3</sub>)<sub>2</sub>]], [[Copper(II) carbonate|CuCO<sub>3</sub>]] | OtherCations = [[Sodium hydroxide|NaOH]], [[Potassium hydroxide|KOH]], [[Magnesium hydroxide|Mg(OH)<sub>2</sub>]],<br /> [[Calcium hydroxide|Ca(OH)<sub>2</sub>]], [[Nickel(II) hydroxide|Ni(OH)<sub>2</sub>]], [[Aluminium hydroxide|Al(OH)<sub>3</sub>]] }} }} '''Copper(II) hydroxide''' ([[chemical formula]] Cu(OH)<sub>2</sub>) is the [[hydroxide]] of the [[metal]] [[copper]]. Copper hydroxide is a pale blue, gelatinous solid. Some forms of copper(II) hydroxide are sold as "stabilized" copper hydroxide, quite likely a mixture of copper(II) carbonate and hydroxide. These are often greener in color. ==History== Copper(II) hydroxide has been known to man since [[copper]] [[smelting]] began around 5000 BCE although the [[alchemy|alchemists]] were probably the first to manufacture it.<ref>Richard Cowen, [http://www.geology.ucdavis.edu/~cowen/~GEL115/115CH3.html ''Essays on Geology, History, and People'', Chapter 3: "Fire and Metals: Copper"].</ref> This was easily done by mixing solutions of [[lye]] and [[blue vitriol]], both chemicals which were known in antiquity. It was produced on an industrial scale during the 17<sup>th</sup> and 18<sup>th</sup> centuries for use in [[pigments]] such as [[blue verditer]] and [[Bremen green]].<ref>Tony Johansen, [http://www.paintmaking.com/historic_pigments.htm ''Historic Artist's Pigments'']. PaintMaking.com. 2006.</ref> These [[pigments]] were used in [[ceramics (art)|ceramics]] and [[painting]].<ref>[http://www.naturalpigments.com/detail.asp?PRODUCT_ID=417-11B ''Blue verditer'']. Natural Pigments. 2007.</ref> ==Chemical Properties== ===Synthesis=== Copper(II) hydroxide can be produced by adding a small amount of [[sodium hydroxide]] to a dilute solution of [[copper(II) sulfate]] (CuSO<sub>4</sub> · 5H<sub>2</sub>O). The precipitate produced in this manner, however, often contains an appreciable amount of [[sodium hydroxide]] impurity and a purer product can be attained if [[ammonium chloride]] is added to the solution beforehand. Alternatively, copper hydroxide is readily made by [[electrolysis of water]] (containing a little [[electrolyte]] such as [[sodium bicarbonate]]). A copper [[anode]] is used, often made from scrap copper. "Copper in moist air slowly acquires a dull green coating. The green material is a 1:1 mole mixture of Cu(OH)<sub>2</sub> and CuCO<sub>3</sub>."<ref>Masterson, W. L., & Hurley, C. N. (2004). ''Chemistry: Principles and Reactions, 5th Ed''. Thomson Learning, Inc. (p 331)"</ref> 2Cu(s) + H<sub>2</sub>O(g) + CO<sub>2</sub>(g) + O<sub>2</sub>(g) ---> Cu(OH)<sub>2</sub>(s) + CuCO<sub>3</sub>(s) This is the [[patina]] that forms on [[bronze]] and other [[copper]] [[alloy]] statues such as the [[Statue of Liberty]]. ===Reactions=== Moist samples of copper(II) hydroxide slowly turn black due to the formation of [[copper(II) oxide]].<ref>Watts, Henry (1872). ''A Dictionary of Chemistry and the Allied Branches of Other Sciences, Vol 2''. Longmans, Green, and Co. (p 69).</ref> When it is dry, however, copper(II) hydroxide does not decompose unless it is heated to 185°C.<ref>[http://ceramic-materials.com/cermat/material/2252.html ''Copper (II) hydroxide'']. Ceramic Materials Database. 2003.</ref> Copper(II) hydroxide reacts with a solution of [[ammonia]] to form a deep blue solution consisting of the [Cu(NH<sub>3</sub>)<sub>4</sub>]<sup>2+</sup> [[complex (chemistry)|complex ion]], but the hydroxide is reformed when the solution is diluted with water. 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|cellulosic]] [[fiber]]. Since copper(II) hydroxide is mildly [[amphoterism|amphoteric]], it dissolves slightly in concentrated [[alkali]], forming [Cu(OH)<sub>4</sub>]<sup>2-</sup>.<ref>Pauling, Linus (1970). ''General Chemistry''. Dover Publications, Inc. (p 702).</ref> ===Use as an organic reagent=== Copper(II) hydroxide has a rather specialized role in [[organic synthesis]]. Often, when it is utilized for this purpose, it is prepared [[In situ#Chemistry and chemical engineering|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. [[Image:UllmannCu(OH)2.PNG]] Copper(II) hydroxide also converts acid [[hydrazide]]s to [[carboxylic acids]] at room temperature. This is especially useful in synthesizing [[carboxylic acids]] with other fragile [[functional groups]]. The published yields are generally excellent as is the case with the production of [[benzoic acid]] and [[octanoic acid]]. [[Image:Cu(OH)2 CarboxylicAcidCatalyst.PNG]] ==Natural occurrence== Copper(II) hydroxide is found in several different [[copper]] [[minerals]], most notably [[azurite]], [[malachite]], [[antlerite]], and [[brochantite]]. [[Azurite]] (2CuCO<sub>3</sub> • Cu(OH)<sub>2</sub> ) and [[malachite]] (CuCO<sub>3</sub> • Cu(OH)<sub>2</sub>) are [[carbonates]] while [[antlerite]] (CuSO<sub>4</sub> • 2Cu(OH)<sub>2</sub>) and [[brochantite]] (CuSO<sub>4</sub> • 3Cu(OH)<sub>2</sub>) are [[sulfates]]. Copper(II) hydroxide is rarely found as an uncombined [[mineral]] because it slowly reacts with [[carbon dioxide]] from the atmosphere to form a [[basic copper carbonate|basic copper(II) carbonate]]. ==Uses== Copper(II) hydroxide has been used as an alternative to the [[Bordeaux mixture]], a [[fungicide]] and [[nematacide]].<ref>[http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7481.html ''Bordeaux Mixture'']. UC [[Integrated Pest Management|IPM]] online. 2007.</ref> Nowadays, it is disfavored because of environmental contamination problems. Copper(II) hydroxide is also occasionally used as [[ceramic colorants|ceramic colorant]]. ==Precautions== Copper(II) hydroxide is a skin, eye and respiratory irritant. Always wear safety glasses when handling copper hydroxide. In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. ==References== # Roscoe, H. E., & Schorlemmer, C. (1879). ''A Treatise on Chemistry 2nd Ed, Vol 2, Part 2''. MacMillan & Co. (p 498). # Paquette, Leo A. (1995). ''Encyclopedia of Reagents for Organic Synthesis, 8 Volume Set''. Wiley. ISBN 0-4719-3623-5. ==Footnotes== {{reflist}} ==External links== *[http://www.npi.gov.au/database/substance-info/profiles/27.html National Pollutant Inventory - Copper and compounds fact sheet] *[http://physchem.ox.ac.uk/MSDS/CO/copper_II_hydroxide.html Safety Data] [[Category:Copper compounds]] [[Category:Hydroxides]] [[Category:Oxidizing agents]] [[Category:Catalysts]] [[ar:هيدروكسيد نحاس ثنائي]] [[de:Kupfer(II)-hydroxid]] [[hu:Réz(II)-hidroxid]] [[ja:水酸化銅(II)]] [[pl:Wodorotlenek miedzi(II)]]