View source for Basic copper carbonate

{{short description|Chemical compound}}
{{For|the neutral compound|Copper(II) carbonate}}
{{chembox
| Verifiedfields = changed
| Watchedfields  = changed
| verifiedrevid  = 435993456
| Name           = 
| ImageFile      = Copper carbonate basic.jpg
| ImageName      = Basic copper carbonate
| ImageFile2     = Malachite-formula-unit-and-coordination-fade-25-from-xtal-3D-bs-17-25.png
| ImageCaption2  = [[Ball-and-stick model]] of part of the [[crystal structure]] of [[malachite]], highlighting the formula unit
| IUPACName      = Dicopper carbonate dihydroxide
| OtherNames     = copper carbonate hydroxide, cupric carbonate, copper carbonate
| SystematicName = 
| Section1       = {{Chembox Identifiers
|  PubChem = 25503
|  ChemSpiderID = 23796
|  SMILES = C(=O)([O-])[O-].[OH-].[OH-].[Cu+2].[Cu+2]
|  InChI = 1/CH2O3.2Cu.2H2O/c2-1(3)4;;;;/h(H2,2,3,4);;;2*1H2/q;2*+2;;/p-4
|  InChIKey = ZMMDPCMYTCRWFF-XBHQNQODAP
|  StdInChI = 1S/CH2O3.2Cu.2H2O/c2-1(3)4;;;;/h(H2,2,3,4);;;2*1H2/q;2*+2;;/p-4
|  StdInChIKey = ZMMDPCMYTCRWFF-UHFFFAOYSA-J
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo = 12069-69-1
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = GIK928GH0Y
| RTECS = 
}}
| Section2       = {{Chembox Properties	 
| Formula = Cu<sub>2</sub>(OH)<sub>2</sub>CO<sub>3</sub>
| MolarMass = 221.114 g/mol
| Appearance = green powder
| Density = 4 g/cm<sup>3</sup>
| Solubility = insoluble
| MeltingPtC = 200 
| BoilingPtC = 290
| BoilingPt_notes = decomposes
| SolubilityProduct = 7.08·10<sup>−9</sup>
}}
| Section3       = 
| Section4       = {{Chembox Thermochemistry
| DeltaHf = −595 kJ/mol
| Entropy = 88 J/mol·K
}}
| Section5       = 
| Section6       = 
| Section7       = {{Chembox Hazards
| ExternalSDS = [https://web.archive.org/web/20020208185350/http://physchem.ox.ac.uk/MSDS/CO/copper_II_carbonate.html Oxford MSDS]
| LD50 = 159 mg/kg (rat, oral)
| MainHazards = 
| GHSPictograms = {{GHS07}}<ref name="sigma">[https://www.sigmaaldrich.com/US/en/product/sigald/61167 Copper(II) carbonate basic]</ref>
| GHSSignalWord = Warning
| HPhrases = {{H-phrases|302|315|319|335}}<ref name="sigma" />
| PPhrases = {{P-phrases|261|305+351+338}}<ref name="sigma" />
| PEL = TWA 1 mg/m<sup>3</sup> (as Cu)<ref name=PGCH>{{PGCH|0150}}</ref>
| REL = TWA 1 mg/m<sup>3</sup> (as Cu)<ref name=PGCH/>
| IDLH =  TWA 100 mg/m<sup>3</sup> (as Cu)<ref name=PGCH/>
}}
}}
'''Basic copper carbonate''' is a chemical compound, more properly called '''copper(II) carbonate hydroxide'''. It can be classified as a [[coordination polymer]] or a [[salt (chemistry)|salt]].  It consists of [[copper|copper(II)]] bonded to [[carbonate]]  and [[hydroxide]] with formula {{chem2|Cu2(CO3)(OH)2}}. It is a green solid that occurs in nature as the mineral [[malachite]]. It has been used since antiquity as a [[pigment]], and it is still used as such in artist paints, sometimes called '''verditer''', '''green bice''', or '''mountain green'''.<ref name=Ullmann>{{cite book |doi=10.1002/14356007.a07_567.pub2 |chapter=Copper Compounds |title=Ullmann's Encyclopedia of Industrial Chemistry |date=2016 |last1=Zhang |first1=Jun |last2=Richardson |first2=H. Wayne |pages=1–31 |isbn=978-3-527-30673-2 }}</ref>

Sometimes basic copper carbonate refers to {{chem|Cu|3}}({{chem|C|O|3}})<sub>2</sub>({{chem|OH}})<sub>2</sub>, a blue crystalline solid also known as the mineral [[azurite]]. It too has been used as pigment, sometimes under the name '''mountain blue''' or '''blue verditer'''.

Both [[malachite]] and [[azurite]] can be found in the [[verdigris]] [[patina]] that is found on weathered [[brass]], [[bronze]], and [[copper]]. The composition of the patina can vary, in a maritime environment depending on the environment a basic chloride may be present, in an urban environment basic sulfates may be present.<ref>Encyclopedia Of Corrosion Technology (Google eBook), Philip A. Schweitzer P.E.; CRC Press, 2004, {{ISBN|08247-4878-6}}</ref>

This compound is often improperly called (even in chemistry articles) '''copper carbonate''',  '''cupric carbonate''', and similar names.  The true (neutral)  [[copper(II) carbonate]] CuCO<sub>3</sub> is not known to occur naturally.<ref>{{Holleman&Wiberg|page=1263}}</ref>  It is decomposed by water or moisture from the air.  It was synthesized only in 1973 by high temperature and very high pressures.<ref name="SeidelEhrhardt1974">{{cite journal|last1=Seidel|first1=H.|last2=Ehrhardt|first2=H.|last3=Viswanathan|first3=K.|last4=Johannes|first4=W.|title=Darstellung, Struktur und Eigenschaften von Kupfer(II)-Carbonat|journal=Zeitschrift für anorganische und allgemeine Chemie|volume=410|issue=2|year=1974|pages=138–148|issn=0044-2313|doi=10.1002/zaac.19744100207}}</ref>

==Preparation==
[[File:Château Frontenac2010 crop roofs.jpg|160px|thumb|left|Basic copper(II) carbonate [[patina]] on roofs of [[Château Frontenac]].]]
 
Basic copper carbonate is prepared by combining aqueous solutions of [[copper(II) sulfate]] and [[sodium carbonate]]. Basic copper carbonate precipitates from the solution, with release of [[carbon dioxide]] {{chem|C|O|2}}:<ref name="hep">Jack Reginald Irons Hepburn (1927): "The chemical nature of precipitated basic cupric carbonate". Article CCCLXXXVI, ''Journal of the Chemical Society'' (Resumed), volume 1927, pp. 2883–2896. {{doi|10.1039/JR9270002883}}</ref>
:{{chem2|2CuSO4 + 2Na2CO3 + H2O -> Cu2(OH)2CO3 + 2Na2SO4 + CO2}}

Basic copper carbonate can also be prepared by treating aqueous solutions of [[copper(II) sulfate]] with [[sodium bicarbonate]].

[[Copper(II) sulfate]] may also be substituted with [[Copper(II) chloride]].

== Reactions ==
Basic copper carbonate is decomposed by acids, such as solutions of [[hydrochloric acid]] {{chem|H|Cl}}, into the copper(II) salt and carbon dioxide.

In 1794 the French chemist [[Joseph Louis Proust]] (1754–1826) thermally decomposed copper carbonate to CO<sub>2</sub> and CuO, [[cupric oxide]].<ref>{{Cite journal |last=Kapoor |first=Satish C. |date=1965 |title=Berthollet, Proust, and Proportions |url=https://www.jstor.org/stable/27757247 |journal=Chymia |volume=10 |pages=53–110 |doi=10.2307/27757247 |issn=0095-9367|url-access=subscription }}</ref>

The basic copper carbonates, malachite and azurite, both decompose forming H<sub>2</sub>O, CO<sub>2</sub>, and CuO, [[cupric oxide]].<ref name="BrownMackenzie1984">{{cite journal|last1=Brown|first1=I.W.M.|last2=Mackenzie|first2=K.J.D.|last3=Gainsford|first3=G.J.|title=Thermal decomposition of the basic copper carbonates malachite and azurite|journal=Thermochimica Acta|volume=75|issue=1–2|year=1984|pages=23–32|issn=0040-6031|doi=10.1016/0040-6031(84)85003-0}}</ref>

==Uses==
Basic copper carbonate is used to remove thiols and hydrogen sulfide from some gas streams, a process called "sweetening". Like many other copper compounds, it also has been used as an [[algaecide]], [[wood preservative]] and similar applications.  It is a precursor to various catalysts and copper soaps.<ref name=Ullmann/>

Both malachite and azurite, as well as synthetic basic copper carbonate have been used as [[pigment]]s.<ref>Valentine Walsh, Tracey Chaplin, ''Pigment Compendium: A Dictionary and Optical Microscopy of Historical Pigments'', 2008, Routledge, {{ISBN|978-0-7506-8980-9}}</ref> One example of the use of both [[azurite]] and its artificial form blue verditer<ref>[http://colourlex.com/project/blue-verditer/ Blue verditer], ColourLex</ref> is the portrait of the family of [[Balthasar Gerbier]] by [[Peter Paul Rubens]].<ref>Robert L. Feller, Rubens’s: The Gerbier Family: Technical Examination of the Pigments and Paint Layers, ''Studies in the History of Art'', Vol. 5 (1973), pp. 54–74.</ref> The green skirt of Deborah Kip is painted in [[azurite]], [[smalt]], blue verditer (artificial form of azurite), [[yellow ochre]], [[lead-tin-yellow]] and yellow lake. The green color is achieved by mixing blue and yellow pigments.<ref>[http://colourlex.com/project/rubens-the-gerbier-family/ Peter Paul Rubens, The Gerbier Family], ColourLex</ref>

==References==
{{reflist}}

==External links==
{{Commons category|Basic copper carbonate}}
*[https://web.archive.org/web/20130530211504/http://www.npi.gov.au/substances/copper/index.html National Pollutant Inventory – copper and compounds fact sheet]
*[http://colourlex.com/project/azurite/ Azurite] at ColourLex
*[http://colourlex.com/project/blue-verditer/ Blue verditer] at ColourLex
  
{{Clear}}
{{carbonates}}
{{Copper compounds}}

{{DEFAULTSORT:Copper(Ii) Carbonate}}
[[Category:Carbonates]]
[[Category:Copper(II) compounds]]
[[Category:Pyrotechnic colorants]]
[[Category:Hydroxides]]