Copper(II) hydroxide: Difference between revisions

{{citation style|date=September 2011}}

| verifiedrevid = 451665994

| Name = Copper(II) hydroxide

| ImageFile = Copper(II) hydroxide.JPG

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| ImageName = Copper(II) hydroxide

| ImageFile2 = Cupric hydroxide .JPG

| IUPACName = Copper(II) hydroxide

| OtherNames = Cupric hydroxide

| Section1 = {{Chembox Identifiers

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| CASNo_Ref = {{cascite|correct|CAS}}

| PubChem = 164826

| Section2 = {{Chembox Properties

| Formula = Cu(OH)₂

| MolarMass = 97.561 g/mol

| Appearance = Blue or blue-green solid

| Density = 3.368 g/cm³, solid

| Solubility = negligible

| SolubleOther = insoluble in [[ethanol]]; <br> soluble in [[ammonium hydroxide|NH₄OH]], [[potassium cyanide|KCN]]

| SolubilityProduct = 2.20 x 10^-20<ref>Pradyot Patnaik. ''Handbook of Inorganic Chemicals''. McGraw-Hill, 2002, ISBN 0-07-049439-8</ref>

| MeltingPt = 80 °C (decomp into [[Copper(II) oxide|CuO]])

| BoilingPt =

| Section7 = {{Chembox Hazards

| ExternalMSDS = http://www.sciencelab.com/xMSDS-Cupric_Hydroxide-9923594

| EUIndex = Not listed

| MainHazards = Skin, Eye, & Respiratory Irritant

| NFPA-H = 2

| NFPA-F = 0

| NFPA-R = 0

| FlashPt = Non-flammable

| RPhrases =

| SPhrases =

| LD50 = 1000 mg/kg (oral, rat)

| Section8 = {{Chembox Related

| OtherAnions = [[Copper(II) oxide]]<br/>[[Copper(II) carbonate]] <br> [[Copper(II) sulfate]] <br> [[Copper(II) chloride]]

| OtherCations = [[Nickel(II) hydroxide]]<br/>[[Zinc hydroxide]] <br> [[Iron(II) hydroxide]] <br> [[Cobalt hydroxide]]

| OtherCpds = [[Copper(I) oxide]] <br> [[Copper(I) chloride]]

'''Copper(II) hydroxide''' is the [[hydroxide]] of the [[metal]] [[copper]] with the [[chemical formula]] of Cu(OH)₂. 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 since [[Smelting#Copper_and_bronze|copper smelting]] began around 5000 BC 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]] (sodium or potassium hydroxide) and [[blue vitriol]] (copper(II) sulfate), both chemicals which were known 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]].<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>

==Natural occurrence==

Copper(II) hydroxide is found in several different copper [[minerals]], most notably [[azurite]], [[malachite]], [[antlerite]], and [[brochantite]]. [[Azurite]] (2CuCO₃·Cu(OH)₂

) and [[malachite]] (CuCO₃·Cu(OH)₂) are [[carbonates]] while [[antlerite]] (CuSO₄·2Cu(OH)₂) and [[brochantite]] (CuSO₄·3Cu(OH)₂) 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]]. The mineral of the formula Cu(OH)₂ is called spertiniite.

==Synthesis==

Copper(II) hydroxide can be produced by adding a small amount of [[sodium hydroxide]] to a dilute solution of [[copper(II) sulfate]] (CuSO₄ · 5H₂O). The precipitate produced in this manner, however, often contains water molecules and an appreciable amount of sodium hydroxide impurity. A purer product can be attained if [[ammonium chloride]] is added to the solution beforehand. Nevertheless, it is impossible to obtain a pure product; processes for eliminating impurities lead to the destruction of the hydroxide, giving rise to the more stable oxide, CuO.<ref>{{cite journal|author = Y. Cudennec, A. Lecerf|title = The transformation of Cu(OH)2 into CuO, revisited|journal = Solid State Sciences|volume = 5 |pages = 1471–1474|year = 2003|doi = 10.1016/j.solidstatesciences.2003.09.009}}</ref> 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)₂ and CuCO₃."<ref>Masterson, W. L., & Hurley, C. N. (2004). ''Chemistry: Principles and Reactions, 5th Ed''. Thomson Learning, Inc. (p 331)"</ref>

:2 Cu (s) + H₂O (g) + CO₂ (g) + O₂ (g) → Cu(OH)₂ (s) + CuCO₃ (s)

This is the [[patina]] that forms on [[bronze]] and other copper [[alloy]] statues such as the [[Statue of Liberty]].

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(NH₃)₄]²⁺ [[complex (chemistry)|complex ion]]. 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]].

Since copper(II) hydroxide is mildly [[amphoterism|amphoteric]], it dissolves slightly in concentrated [[alkali]], forming [Cu(OH)₄]^2-.<ref>Pauling, Linus (1970). ''General Chemistry''. Dover Publications, Inc. (p 702).</ref>

===Reagent for organic chemistry===

It is sometimes used in the synthesis of [[aryl]] [[amine]]s. 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:{{Citation needed|date=April 2010}}

:[[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]]:{{Citation needed|date=April 2010}}

:[[Image:Cu(OH)2 CarboxylicAcidCatalyst.PNG]]

Copper(II) hydroxide has been used as an alternative to the [[Bordeaux mixture]], a [[fungicide]] and [[nematicide]].<ref>[http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7481.html ''Bordeaux Mixture'']. UC [[Integrated Pest Management|IPM]] online. 2007.</ref> Such products include Dupont's Kocide 3000. Copper(II) hydroxide is also occasionally used as [[ceramic colorants|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.<ref>[http://www.sepro.com/default.php "SePRO Corporation"].</ref> It is now sold as Microkote either in a solution you apply yourself, or as treated pots.

==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 0-471-93623-5.

==Footnotes==

{{Commons cat|Copper(II) hydroxide}}

*[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]]

[[ar:هيدروكسيد النحاس الثنائي]]

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[[it:Idrossido di rame(II)]]

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[[simple:Copper(II) hydroxide]]

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