Copper(II) fluoride: Difference between revisions

{{More footnotes needed|date=June 2021}}

| Verifiedfields = changed

| Watchedfields = changed

| verifiedrevid = 445803924

| Name = Copper(II) fluoride

| ImageFile = Copper(II)-fluoride-unit-cell-3D-bs-17.png

| ImageName = Ball-and-stick model of the unit cell of copper(II) fluoride

| ImageCaption = [[Unit cell]] of the anhydrous form

| ImageFile1 = Copper(II)-fluoride-xtal-packing-3D-bs-17.png

| ImageName1 = Ball-and-stick model of packing in the crystal structure of copper(II) fluoride

| ImageCaption1 = [[Ball-and-stick model]] of crystal packing in the anhydrous form

| ImageFile2 = Fluorid měďnatý.PNG

| ImageName2 = Actual picture

| ImageCaption2 = Dihydrate

| IUPACName = Copper difluoride

| OtherNames = Cupric fluoride; Copper fluoride; Copper (2+) Difluoride

| Section1 = {{Chembox Identifiers

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

| CASNo_Ref = {{cascite|correct|??}}

| CASNo2_Ref = {{cascite|correct|CAS}}

| CASNo2 = 13454-88-1

| CASNo2_Comment = (dihydrate)

| EC_number = 232-147-3

| UNII_Ref = {{fdacite|correct|FDA}}

| UNII = ML04XYE5C1

| UNII2_Ref = {{fdacite|correct|FDA}}

| UNII2 = 3A38PC42E9

| UNII2_Comment = (dihydrate)

| PubChem = 82236

| Section2 = {{Chembox Properties

| Formula = [[Copper|Cu]][[Fluorine|F]]₂

| MolarMass = 101.543 g/mol (anhydrous) <br> 137.573 g/mol (dihydrate)

| Appearance = White crystalline powder<br />When [[Water of crystallization|hydrated]]: Blue

| Density = 4.23 g/cm³ (anhydrous) <br> 2.934 g/cm³ (dihydrate)<ref>Pradyot Patnaik. ''Handbook of Inorganic Chemicals''. McGraw-Hill, 2002, {{ISBN|0-07-049439-8}}</ref>

| Solvent = other solvents

| MeltingPtC = 836

| MeltingPt_notes = (anhydrous) <br> 130&nbsp;°C (dihydrate, decomposes)

| BoilingPtC = 1676

| BoilingPt_notes = (anhydrous)

| MagSus = +1050.0·10⁻⁶ cm³/mol

| Section3 = {{Chembox Hazards

| 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/>

| Section8 = {{Chembox Related

| OtherAnions = [[Copper(II) bromide]]<br />[[Copper(II) chloride]]

| OtherCations = [[Silver(II) fluoride]]<br />[[Cobalt(II) fluoride]]

| OtherCompounds = [[Copper(I) fluoride]] }}

}}

'''Copper(II) fluoride''' is an [[inorganic compound]] with the chemical formula CuF₂. The [[anhydrous]] form is a white, [[Ionic compound|ionic]], crystalline, [[Hygroscopy|hygroscopic]] salt with a distorted [[rutile]]-type [[crystal structure]], similar to other fluorides of chemical formulae MF₂ (where M is a metal). The [[Hydrate#Inorganic_chemistry|dihydrate]], {{chem2|CuF2*2H2O}}, is blue in colour.<ref name="G&E">{{Greenwood&Earnshaw2nd|pages=1184–1185}}</ref>

==Structure==

Copper(II) fluoride has a [[monoclinic crystal system|monoclinic crystal structure]]<ref name="FHSG">{{ cite journal | title = Magnetic and crystal structure of copper(II) fluoride | first1 = P. | last1 = Fischer | first2 = W. | last2 = Hälg | first3 = D.| last3 = Schwarzenbach | first4 = H. | last4 = Gamsjäger | journal = [[Journal of Physics and Chemistry of Solids|J. Phys. Chem. Solids]] | volume = 35 | issue = 12 | year = 1974 | pages = 1683–1689 | doi = 10.1016/S0022-3697(74)80182-4 }}</ref> and cannot achieve a higher-symmetry structure. It forms rectangular prisms with a parallelogram base.<ref>{{cite journal |author1=C. Billy |author2=H. M. Haendler | title= The Crystal Structure of Copper(II) Fluoride | journal= [[Journal of the American Chemical Society]] | year=1957 | volume=79 | pages= 1049–51|doi = 10.1021/ja01562a011 | issue= 5}}</ref> Each copper ion has four neighbouring fluoride ions at 1.93 Å separation and two further away at 2.27 Å.<ref name="G&E" /> This [[Octahedral molecular geometry#Deviations_from_ideal_symmetry|distorted octahedral]] [4+2] [[coordination geometry|coordination]] is a consequence of the [[Jahn–Teller effect]] in [[d electron count|d⁹]] copper(II),<ref name="JT_G&E">{{Greenwood&Earnshaw2nd|pages=1190–1191}}</ref> and leads to a distorted rutile structure similar to that of [[chromium(II) fluoride]], {{chem2|CrF2}}, which is a [[d electron count|d⁴ compound]].<ref name="G&E" />

{| class="wikitable" style="margin:1em auto; text-align:center;"

|+Coordination in copper(II) fluoride<ref name="G&E" /><ref name="FHSG" />

|-

! Copper coordination

! Fluorine coordination

|-

| [[File:Copper(II)-fluoride-Cu-coord-3D-bs-17.png|150px]]

| [[File:Copper(II)-fluoride-F-coord-3D-bs-17.png|150px]]

|}

Cupric fluoride catalyzes the decomposition of [[nitric oxides]] in emission control systems.<ref>{{Kirk-Othmer|doi=10.1002/0471238961.0315161613051908.a01|title=Fluorine compounds, inorganic, copper|first1=Dayal&nbsp;T.|last1=Meshri|year=2000}}</ref>

Copper (II) fluoride can be used to make fluorinated aromatic hydrocarbons by reacting with [[aromatic hydrocarbon]]s in an [[oxygen]]-containing atmosphere at temperatures above 450&nbsp;°C (842 °F). This reaction is simpler than the [[Sandmeyer reaction]], but is only effective in making compounds that can survive at the temperature used. A coupled reaction using oxygen and 2 HF regenerates the copper(II) fluoride, producing water.<ref>{{cite journal |author1=M. A. Subramanian |author2=L. E. Manzer | title= A "Greener" Synthetic Route for Fluoroaromatics via Copper (II) Fluoride | journal = [[Science (journal)|Science]] | year=2002 | volume=297 | pages= 1665|doi = 10.1126/science.1076397| pmid= 12215637 | issue= 5587|s2cid=32697750 }}</ref> This method has been proposed as a "greener" method of producing fluoroaromatics since it avoids producing toxic waste products such as [[ammonium fluoride]].

Copper(II) fluoride can be synthesized from [[copper]] and [[fluorine]] at temperatures of 400&nbsp;°C (752 °F). It occurs as a direct reaction.

It loses fluorine in the molten stage at temperatures above 950&nbsp;°C (1742 °F).

The complex anions of CuF₃⁻, CuF₄²⁻ and CuF₆⁴⁻

==Solubility==

Copper(II) fluoride is slightly soluble in water, but starts to decompose when it is in hot water, producing basic F⁻ and Cu(OH) ions.{{citation needed|date=November 2020}}

==Toxicity==

There is little specific information on the toxicity of Copper(II) fluoride.

[[Copper toxicity]] can affect the skin, eyes, and respiratory tract. Serious conditions include metal fume fever, and [[hemolysis]] of red blood cells. Copper can also cause damage to the liver and other major organs.

Metal fluorides are generally safe at low levels and are [[Water fluoridation|added to water]] in many countries to protect against tooth decay. At higher levels they can cause [[Fluoride toxicity|toxic effects]] ranging from nausea and vomiting to tremors, breathing problems, serious convulsions and even coma. Brain and kidney damage can result. Chronic exposure can cause losses in bone density, weight loss and anorexia.

==Hazards==

Experiments using copper(II) fluoride should be conducted in a fume hood because metal oxide fumes can occur. The combination of acids with copper(II) fluoride may lead to the production of [[hydrogen fluoride]], which is highly toxic and corrosive.

*{{cite journal |author1=P. C. de Mello |author2=M. Hehenberg |author3=S. Larson |author4=M. Zerner | title= Studies of the electronic structure of copper fluorides and copper chlorides | journal= [[Journal of the American Chemical Society]] | year=1980 | volume=102 | pages= 1278–1288|doi =10.1021/ja00524a010 | issue= 4 }}

*{{cite journal |author1=H. M. Haendler |author2=L. H. Towle |author3=E. F. Bennett |author4=W. L. Patterson | title=The Reaction of Fluorine with Copper and Some of its Compounds. Some Properties of Copper(II) Fluoride | journal= [[Journal of the American Chemical Society]] | year=1954 | volume=76 | pages= 2178–2179|doi =10.1021/ja01637a039 | issue= 8 }}

*{{cite journal |author1=T. C. Ehlert |author2=J. S. Wang | title= Thermochemistry of the copper fluorides | journal= [[Journal of Physical Chemistry]] | year=1977 | volume=81 | pages= 2069–2073|doi = 10.1021/j100537a005 | issue= 22}}

*Dierks, S. "Copper Fluoride". http://www.espimetals.com/index.php/msds/537-copper-fluoride (accessed October 9).

* {{cite journal | last1 = Subramanian | first1 = M. A. | author-link = Mas Subramanian | last2 = Manzer | first2 = L. E. | year = 2002 | title = A 'Greener' Synthetic Route for Fluoroaromantics via Copper (II) Fluoride | journal = Science | volume = 297 | issue = 5587| page = 1665 | doi=10.1126/science.1076397 | pmid=12215637| s2cid = 32697750 }}

*{{cite journal | last1 = Olejniczak | first1 = I. | last2 = Wolak | first2 = J. | last3 = Barszcz | first3 = B. | last4 = Schlueter | first4 = J. | last5 = Manson | first5 = J. | year = 2010 | title = CuF₂ Structural Changes in Two-Dimensional Quantum Magnet (H₂O)₂(pyz) Under Pressure: Raman Study | doi = 10.1063/1.3482697 | journal = AIP Conference Proceedings | volume = 1267 | issue = 1| pages = 597–598 | bibcode = 2010AIPC.1267..597O }}

*{{cite journal | last1 = Kent | first1 = R. A. | last2 = Mcdonald | first2 = J. D. | last3 = Margrave | first3 = J. L. | year = 1966 | title = Mass Spectrometric Studies at High Temperatures. IX. The Sublimation Pressure of Copper(II) Fluoride | journal = Journal of Physical Chemistry | volume = 70 | issue = 3| pages = 874–877 | doi=10.1021/j100875a042}}

*{{cite journal | last1 = Shashkin | first1 = S. Y. | last2 = Goddard III | first2 = W. A. | year = 1986 | title = Electron Correlation effects in ligand field parameters and other properties of copper II fluoride | doi = 10.1021/j100274a010 | journal = Journal of Physical Chemistry | volume = 90 | issue = 2| pages = 250–255 }}

{{Commons category|Copper(II) fluoride}}

*[https://web.archive.org/web/20080302034606/http://www.npi.gov.au/database/substance-info/profiles/27.html National Pollutant Inventory - Copper and compounds fact sheet]

*[https://web.archive.org/web/20060116134617/http://www.npi.gov.au/database/substance-info/profiles/44.html National Pollutant Inventory - Fluoride and compounds fact sheet]

{{fluorides}}

[[Category:Metal halides]]

[[Category:Copper(II) compounds]]