Basic copper carbonate: Difference between revisions

{{short description|Chemical compound}}

{{For|the neutral compound|Copper(II) carbonate}}

| Verifiedfields = changed

| Watchedfields = changed

| verifiedrevid = 435993456

| Name =

| ImageFile = Copper carbonate basic.jpg

| ImageName = Basic copper carbonate

| ImageFile1 = Basic-copper-carbonate-3D-vdW.png

| ImageCaption1 = [[Space-filling model]] of the [[formula unit]] of 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, Greenium

| 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 = Cu₂(OH)₂CO₃

| MolarMass = 221.114 g/mol

| Appearance = green powder

| Density = 4 g/cm³

| Solubility = insoluble

| MeltingPtC = 200

| BoilingPtC = 290

| BoilingPt_notes = decomposes

| SolubilityProduct = 7.08·10⁻⁹

}}

| 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/m³ (as Cu)<ref name=PGCH>{{PGCH|0150}}</ref>

| REL = TWA 1 mg/m³ (as Cu)<ref name=PGCH/>

| IDLH = TWA 100 mg/m³ (as Cu)<ref name=PGCH/>

}}

}}

'''Basic copper carbonate''' is a chemical compound, more properly called '''copper(II) carbonate hydroxide'''. It is an [[ionic compound]] (a [[salt (chemistry)|salt]]) consisting of the [[ion]]s [[copper|copper(II)]] {{chem|Cu|2+}}, [[carbonate]] {{chem|C|O|3|2-}}, and [[hydroxide]] {{chem|O|H|-}}.

The name most commonly refers to the compound with formula {{chem|Cu|2|C|O|3}}({{chem|OH}})₂. It is a green crystalline 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'''.

Sometimes the name is used for {{chem|Cu|3}}({{chem|C|O|3}})₂({{chem|OH}})₂, 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]] CuCO₃ is not known to occur naturally.<ref>{{Holleman&Wiberg|page=1263}}</ref> It is decomposed by water or moisture from the air, and 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>

[[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]] at [[standard conditions for temperature and pressure|ambient temperature and pressure]]. 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>

<chem>2CuSO4 + 2Na2CO3 + H2O -> Cu2(OH)2CO3 + 2Na2SO4 + CO2</chem>

Basic copper carbonate can also be prepared by reacting aqueous solutions of [[copper(II) sulfate]] and [[sodium bicarbonate]] at ambient conditions. Basic copper carbonate precipitates from the solution, again with release of carbon dioxide:

<chem>2CuSO4 + 4NaHCO3 -> Cu2(OH)2CO3 + 2Na2SO4 + 3CO2 + H2O</chem>

[[Copper(II) sulfate]] may also be substituted with [[Copper(II) chloride]], creating [[Sodium chloride]] (NaCl) as a byproduct instead of [[Sodium sulfate]] (Na₂SO₄), both of which are soluble in water.

== 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 CO₂ 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}}</ref>

The basic copper carbonates, malachite and azurite, both decompose forming H₂O, CO₂, 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==

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>

It has also been used in some types of make-up, like [[lipstick]], although it can also be toxic to humans. It also has been used for many years as an effective [[algaecide]].

{{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}}

[[Category:Copper(II) compounds]]

[[Category:Hydroxides]]