{{Distinguish|Copper(I) nitrate}} {{chembox | Verifiedfields = changed | Watchedfields = changed | verifiedrevid = 476996432 | Name = Copper(II) nitrate | ImageFile1 = Copper(II)-nitrate-trihydrate-sample.jpg | ImageCaption1 = Trihydrate | ImageFileL2 = Anhydrous-copper(II)-nitrate-unit-cell-3D-bs-17.png | ImageClassL2 = bg-transparent | ImageFileR2 = Beta-copper(II)-nitrate-unit-cell-3D-bs-17.png | ImageClassR2 = bg-transparent | ImageCaptionL2 = alpha polymorph<ref name="Wallwork&Addison" /> | ImageCaptionR2 = beta polymorph<ref name="Troyanov" /> | IUPACName = Copper(II) nitrate | OtherNames = Cupric nitrate | Section1 = {{Chembox Identifiers |ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} |ChemSpiderID = 17582 |UNII_Ref = {{fdacite|correct|FDA}} |UNII = 9TC879S2ZV |UNII1_Ref = {{fdacite|correct|FDA}} |UNII1 = 066PG1506T |UNII1_Comment = (trihydrate) |UNII2_Ref = {{fdacite|correct|FDA}} |UNII2 = 0HP2H86BS6 |UNII2_Comment = (hexahydrate) |InChI = 1/Cu.2NO3/c;2*2-1(3)4/q+2;2*-1 |SMILES = [Cu+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O |InChIKey = XTVVROIMIGLXTD-UHFFFAOYAG |PubChem = 18616 |PubChem1 = 9837674 |PubChem1_Comment = (trihydrate) |PubChem2 = 9839123 |PubChem2_Comment = (hexahydrate) |StdInChI_Ref = {{stdinchicite|correct|chemspider}} |StdInChI = 1S/Cu.2NO3/c;2*2-1(3)4/q+2;2*-1 |StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} |StdInChIKey = XTVVROIMIGLXTD-UHFFFAOYSA-N |CASNo = 3251-23-8 |CASNo_Ref = {{cascite|correct|CAS}} |CASNo1_Ref = {{cascite|correct|CAS}} |CASNo1 = 10031-43-3 |CASNo1_Comment = (trihydrate) |CASNo2_Ref = {{cascite|correct|CAS}} |CASNo2 = 13478-38-1 |CASNo2_Comment = (hexahydrate) |CASNo3_Ref = {{cascite|changed|??}} |CASNo3 = 19004-19-4 |CASNo3_Comment = (hemipentahydrate) |RTECS = GL7875000 |ChEBI_Ref = {{ebicite|changed|EBI}} |ChEBI = 78036 }} | Section2 = {{Chembox Properties |Formula = {{chem2|Cu(NO3)2}} |MolarMass = {{ubl |{{val|187.5558|u=g/mol}} (anhydrous) |{{val|241.60|u=g/mol}} (trihydrate) |{{val|232.591|u=g/mol}} (hemipentahydrate) }} |Appearance = {{ubl |blue-green crystals (anhydrous) |blue crystals (hydrate) }} |Density = {{ubl |{{val|3.05|u=g/cm3}} (anhydrous) |{{val|2.32|u=g/cm3}} (trihydrate) |{{val|2.07|u=g/cm3}} (hexahydrate) }} |Solubility ={{ubl |trihydrate:<ref name="Perrys7th">{{cite book |title=Perry's chemical engineers' handbook |date=1997 |publisher=McGraw-Hill |location=New York |isbn=0070498415 |edition=7th}}{{page needed|date=November 2025}}</ref> |{{val|381|u=g/100 mL}} ({{convert|40|C|F K}}) |{{val|666|u=g/100 mL}} ({{convert|80|C|F K}}) |hexahydrate: |{{val|243.7|u=g/100 mL}} ({{convert|80|C|F K}}) }} |Solvent1 = ethanol |Solubility1 = hydrates very soluble |Solvent2 = ammonia |Solubility2 = hydrates very soluble |MeltingPt_notes = {{ubl |{{convert|114|C|F K}} (anhydrous) |{{convert|80|C|F K}} (trihydrate, decomposes) |{{convert|26.4|C|F K}} (hexahydrate, decomposes) }} |MeltingPt_ref = {{cn|date=November 2025}} |BoilingPtC = 170 |BoilingPt_notes = (trihydrate, decomposes) |BoilingPt_ref = {{cn|date=November 2025}} |MagSus = {{val|1570.0|e=-6|u=cm3/mol}} (trihydrate) }} | Section3 = {{Chembox Structure | CrystalStruct = {{ubl |orthorhombic (anhydrous) |rhombohedral (hydrates) }} }} | Section7 = {{Chembox Hazards |MainHazards = Irritant, Oxidizer |GHS_ref=<ref name="Sigma">{{Sigma-Aldrich |id=229636 |name=Copper(II) nitrate}}</ref> |GHSPictograms = {{GHS02}}{{GHS05}}{{GHS09}} |GHSSignalWord=Danger |HPhrases={{H-phrases|272|314|410}} |PPhrases={{P-phrases|210|220|221|260|264|273|280|301+330+331|303+361+353|304+340+310|305+351+338+310|363|370+378|391|405|501}} |NFPA-H =3 |NFPA-F =3 |NFPA-R =3 |NFPA-S = OX |NFPA_ref = <ref name="FisherSDS">{{cite web |title=SDS - Copper(II) nitrate |url=https://www.fishersci.com/store/msds?partNumber=AC207681000&productDescription=COPPER+II+NITRATE+TRIHY+100GR&vendorId=VN00032119&countryCode=US&language=en |website=fishersci.com |publisher=ThermoFisher Scientific |access-date=6 November 2025 |date=24 December 2021}}</ref> |PEL ={{val|1|u=mg/m3}} (TWA, as Cu) |REL = {{val|1|u=mg/m3}} (TWA, as Cu) |IDLH = {{val|100|u=mg/m3}} (TWA, as Cu) |NIOSH_id=0150 }} | Section8 = {{Chembox Related |OtherAnions = {{ubl |Copper(II) sulfate |Copper(II) chloride }} |OtherCations = {{ubl |Silver nitrate |Gold(III) nitrate }} }} }}
'''Copper(II) nitrate''' describes any member of the family of inorganic compounds with the formula {{chem2|Cu(NO3)2*x(H2O)}}. The hydrates are hygroscopic blue solids. Anhydrous copper nitrate forms blue-green crystals and sublimes in a vacuum at {{convert|150|-|200|C|F}}.<ref>{{cite book |last=Pass and Sutcliffe |title=Practical Inorganic Chemistry |year=1968 |publisher=Chapman and Hall |location=London}}</ref><ref name="G&E">{{Greenwood&Earnshaw2nd|page=1190}}</ref> Common hydrates are the hemipentahydrate and trihydrate.
==Occurrence== No mineral of the ideal {{chem2|Cu(NO3)}} formula, or the hydrates, are known.
{{ill|Likasite|it}}, {{chem2|Cu3(NO3)(OH)5*2H2O}} and {{ill|buttgenbachite|it}}, {{chem2|Cu19(NO3)2(OH)32Cl4*2H2O}} are related minerals. {{anchor|gerhardtite}} Natural basic copper nitrates include the rare minerals gerhardtite and {{ill|rouaite|it}}, both being polymorphs of {{chem2|Cu2(NO3)(OH)3}}. A much more complex, basic, hydrated and chloride-bearing natural salt is buttgenbachite.<ref name=min811>{{Cite web |url=https://www.mindat.org/min811.html |title=Buttgenbachite |website=www.mindat.org}}</ref><ref>{{Cite web |url=https://www.mindat.org/min-1680.html |title=Gerhardtite |website=www.mindat.org}}</ref><ref>{{Cite web |url=https://www.mindat.org/min-10588.html |title=Rouaite |website=www.mindat.org}}</ref><ref name=min2399>{{Cite web |url=https://www.mindat.org/min2399.html |title=Likasite |website=www.mindat.org}}</ref>
==Structure== ===Anhydrous copper(II) nitrate=== thumb|class=skin-invert-image|left|Structure of anhydrous copper(II) nitrate in the gas phase.<ref name="G&E" />
Two polymorphs of anhydrous copper(II) nitrate, α and β, are known. Both polymorphs are three-dimensional coordination polymer networks with infinite chains of copper(II) centers and nitrate groups. The α form has only one Cu environment, with [4+1] coordination, but the β form has two different copper centers, one with [4+1] and one that is square planar.<ref name="G&E" /><ref name="Wallwork&Addison">{{cite journal |last1=Wallwork |first1=S. C. |last2=Addison |first2=W. E. |year=1965 |title=526. The crystal structures of anhydrous nitrates and their complexes. Part I. The α form of copper(II) nitrate |journal=J. Chem. Soc. |volume=1965 |pages=2925–2933 |doi=10.1039/JR9650002925}}</ref><ref name=Troyanov>{{cite journal |last1=Troyanov |first1=S. I. |last2=Morozov |first2=I. V. |last3=Znamenkov |first3=K. O. |last4=Yu |last5=Korenev |first5=M. |year=1995 |title=Synthesis and X-Ray Structure of New Copper(II) Nitrates: Cu(NO<sub>3</sub>)<sub>2</sub>·H<sub>2</sub>O and β-modification of Cu(NO<sub>3</sub>)<sub>2</sub> |journal=Z. Anorg. Allg. Chem. |volume=621 |issue=7 |pages=1261–1265 |doi=10.1002/zaac.19956210727}}</ref>
The nitromethane solvate also features "[4+1] coordination", with four short Cu-O bonds of approximately 200 pm and one longer bond at 240 pm.<ref>{{cite journal |last1=Duffin |first1=B. |last2=Wallwork |first2=S. C. |year=1966 |title=The crystal structure of anhydrous nitrates and their complexes. II. The 1:1 copper(II) nitrate-nitromethane complex |journal=Acta Crystallographica |volume=20 |issue=2 |pages=210–213 |doi=10.1107/S0365110X66000434 |doi-access=}}</ref>
Heating solid anhydrous copper(II) nitrate under a vacuum to {{convert|150|-|200|C|F}} leads to sublimation and cracking to give a vapour of monomeric copper(II) nitrate molecules. In the vapour phase, the molecule features two bidentate nitrate ligands.<ref name="G&E" /><ref>{{cite journal |title=628. The vapour pressure of anhydrous copper nitrate, and its molecular weight in the vapour state |first1=C. C. |last1=Addison |first2=B. J. |last2=Hathaway |journal=Journal of the Chemical Society |year=1958 |pages=3099-3106 |doi=10.1039/JR9580003099}}</ref><ref>{{cite journal |last1=LaVilla |first1=R. E. |last2=Bauer |first2=S. H. |year=1963 |title=The Structure of Gaseous Copper(II) Nitrate as Determined by Electron Diffraction |journal=J. Am. Chem. Soc. |volume=85 |issue=22 |pages=3597–3600 |doi=10.1021/ja00905a015}}</ref>
===Hydrated copper(II) nitrate=== Five hydrates have been reported: the monohydrate ({{chem2|Cu(NO3)2*2H2O}}), the sesquihydrate ({{chem2|2Cu(NO3)2*3H2O}}), the hemipentahydrate ({{chem2|Cu(NO3)2*2.5H2O}}), a trihydrate ({{chem2|Cu(NO3)2*3H2O}}),{{cn|reason=There was a cite here, but with no title and in Czech I'm not multilingually psychic and can't figure out what whoever added it was referring to.|date=November 2025}} and a hexahydrate ({{chem2|[Cu(OH2)6](NO3)2}}.<ref name=Troyanov/><ref>{{cite journal |last1=Dornberger-Schiff |first1=K. |last2=Leciejewicz |first2=J. |year=1958 |title=Zur Struktur des Kupfernitrates Cu(NO<sub>3</sub>)<sub>2</sub><sup>.</sup>1.5H<sub>2</sub>O |journal=Acta Crystallographica |volume=11 |issue=11 |pages=825–826 |doi=10.1107/S0365110X58002322 |doi-access=}}</ref><ref>{{cite journal |last1=Morosin |first1=B. |year=1970 |title=The crystal structure of Cu(NO<sub>3</sub>)<sub>2</sub>.2.5H<sub>2</sub>O |journal=Acta Crystallographica Section B |volume=26 |issue=9 |pages=1203–1208 |doi=10.1107/S0567740870003898}}</ref><ref>{{cite journal |last1=Zibaseresht |first1=R. |last2=Hartshorn |first2=R. M. |year=2006 |title=Hexaaquacopper(II) dinitrate: absence of Jahn-Teller distortion |journal=Acta Crystallographica Section E |volume=62 |pages=i19–i22 |doi=10.1107/S1600536805041851}}</ref>
The crystal structure of the hexahydrate appeared to show six almost equal {{chem2|Cu\sO}} distances, not revealing the usual effect of a Jahn-Teller distortion that is otherwise characteristic of octahedral Cu(II) complexes. This non-effect was attributed to the strong hydrogen bonding that limits the elasticity of the {{chem2|Cu\sO}} bonds but it is probably due to nickel being misidentified as copper in the refinement.{{cn|date=November 2025}}
==Synthesis and reactions== ===Hydrated copper(II) nitrate === Hydrated copper nitrate is prepared by treating copper metal or its oxide with nitric acid:<ref name=Ullmann/>
:{{chem2|Cu + 4 HNO3 -> Cu(NO3)2 + 2 H2O + 2 NO2}}
The same salts can be prepared treating copper metal with an aqueous solution of silver nitrate. That reaction illustrates the ability of copper metal to reduce silver ions.{{cn|date=November 2025}}
In aqueous solution, the hydrates exist as the aqua complex {{chem2|[Cu(H2O)6](2+)}}. Such complexes are highly labile and subject to rapid ligand exchange due to the d{{sup|9}} electronic configuration of copper(II).{{cn|date=November 2025}}
Attempted dehydration of any of the hydrated copper(II) nitrates by heating affords the oxides, not {{chem2|Cu(NO3)2}}.<ref name="G&E" /> At {{convert|80|C|F}} the hydrates convert to "basic copper nitrate", {{chem2|Cu2(NO3)(OH)3}}, which converts to {{chem2|CuO}} at {{convert|180|C|F}}.<ref name=Ullmann/> Exploiting this reactivity, copper nitrate can be used to generate nitric acid by heating it until decomposition and passing the fumes directly into water. This method is similar to the last step in the Ostwald process. The equations are as follows:{{cn|date=November 2025}}
:{{chem2|2 Cu(NO3)2 -> 2 CuO + 4 NO2 + O2}} :{{chem2|3 NO2 + H2O -> 2 HNO3 + NO}}
Treatment of copper(II) nitrate solutions with triphenylphosphine, triphenylarsine, and triphenylstibine gives the corresponding copper(I) complexes {{chem2|[Cu(RPh3)3]NO3}} (E = P, As, Sb). The group V ligand is oxidized to the oxide.<ref>{{cite book |last1=Gysling |first1=Henry J. |title=Inorganic Syntheses |series=Inorganic Syntheses |year=1979 |volume=19 |pages=92–97 |chapter=Coordination Complexes of Copper(I) Nitrate |doi=10.1002/9780470132500.ch19 |isbn=9780470132500}}</ref>
===Anhydrous copper(II) nitrate === Anhydrous {{chem2|Cu(NO3)2}} is one of the few anhydrous transition metal nitrates. It cannot be prepared by reactions containing or producing water. Instead, anhydrous {{chem2|Cu(NO3)2}} forms when copper metal is treated with dinitrogen tetroxide:<ref>{{cite journal |doi=10.1039/qr9712500289 |title=Structural Aspects of Co-ordinated Nitrate Groups |year=1971 |last1=Addison |first1=C. C. |last2=Logan |first2=N. |last3=Wallwork |first3=S. C. |last4=Garner |first4=C. D. |journal=Quarterly Reviews, Chemical Society |volume=25 |issue=2 |page=289}}</ref><ref name="G&E" />
:{{chem2|Cu + 2 N2O4 -> Cu(NO3)2 + 2 NO}}
==Applications== Copper(II) nitrate finds a variety of applications, the main one being its conversion to copper(II) oxide, which is used as catalyst for a variety of processes in organic chemistry. Its solutions are used in textiles and polishing agents for other metals.<ref name=Ullmann>{{Ullmann |first=H.Wayne |last=Richardson |title=Copper Compounds |doi=10.1002/14356007.a07_567}}.</ref> It is often used in school laboratories to demonstrate chemical voltaic cell reactions.{{cn|date=November 2025}} It is a component in some ceramic glazes and metal patinas.{{cn|date=November 2025}}
===Organic synthesis=== Copper nitrate, in combination with acetic anhydride, is an effective reagent for nitration of aromatic compounds, known as the Menke nitration.<ref>{{cite journal |author=Menke J.B. |title=Nitration with nitrates |journal=Recueil des Travaux Chimiques des Pays-Bas |volume=44 |year=1925 |pages=141 |doi=10.1002/recl.19250440209}}</ref>
Hydrated copper nitrate adsorbed onto clay affords a reagent called "Claycop". The resulting blue-colored clay is used as a slurry, for example for the oxidation of thiols to disulfides. Claycop is also used to convert dithioacetals to carbonyls.<ref>{{cite book |last1=Balogh |first1=M. |editor1-last=Paquette |editor1-first=L. |chapter=Copper(II) Nitrate–K10 Bentonite Clay |title=Encyclopedia of Reagents for Organic Synthesis |date=15 April 2001 |publisher=J. Wiley & Sons |location=New York |doi=10.1002/047084289X}}</ref> A related reagent based on montmorillonite has proven useful for the nitration of aromatic compounds.<ref>{{cite journal |doi=10.1002/anie.199005351 |volume=29 |issue=5 |title=Clays Direct Aromatic Nitration |year=1990 |journal=Angewandte Chemie International Edition in English |pages=535–536 |last1=Collet |first1=Christine}}</ref>
=== Electrowinning === Copper(II) nitrate may also be used for copper electrowinning on small scale with a ammonia ({{chem2|NH3}}) as a byproduct.<ref>{{Cite journal |last=Oishi |first=Tetsuo |last2=Koyama |first2=Kazuya |last3=Konishi |first3=Hirokazu |last4=Tanaka |first4=Mikiya |last5=Lee |first5=Jae-Chun |date=November 2007 |title=Influence of ammonium salt on electrowinning of copper from ammoniacal alkaline solutions |url=https://linkinghub.elsevier.com/retrieve/pii/S001346860700802X |journal=Electrochimica Acta |language=en |volume=53 |issue=1 |pages=127–132 |doi=10.1016/j.electacta.2007.06.024|url-access=subscription }}</ref>
==References== {{Reflist}}
==External links== {{Commons category|Copper(II) nitrate}}
{{Copper compounds}} {{nitrates}}
Category:Copper(II) compounds Category:Nitrates Category:Oxidizing agents