copper(I) thiocyanate
{{chembox
| Name =
| ImageFile = Тиоцианат меди(I) (synthesized and photographed by Paliienko Konstantin).jpg
| ImageFile1 = CuSCN-beta.png
| ImageCaption = Copper(I) thiocyanate
| ImageSize1 = 130px
| ImageSize = 250px
| IUPACName =
| OtherNames = Cuprous thiocyanate
| SystematicName =
| Section1 = {{Chembox Identifiers
| CASNo = 1111-67-7
| CASNo_Ref = {{cascite|correct|CAS}}
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = PW2155WE9H
| PubChem = 11029823
| ChemSpiderID = 55204
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| Section2 = {{Chembox Properties
| Formula = CuSCN
| Appearance = white powder
| BoilingPt =
| Solubility = 8.427·10−7 g/L (20 °C)
| SolubilityProduct = 1.77{{e|−13}}{{cite book |author1=John Rumble |title=CRC Handbook of Chemistry and Physics |date=June 18, 2018 |publisher=CRC Press |isbn=978-1138561632 |pages=5–188|edition=99 |language=English}}
| MagSus = −48.0·10−6 cm3/mol
}}
| Section3 =
| Section4 =
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| Section6 =
| Section7 = {{Chembox Hazards
| ExternalSDS =
| MainHazards =
| FlashPt =
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| Section8 = {{Chembox Related
| OtherAnions = Copper(I) iodide, copper(I) cyanide
| OtherCations = Copper(II) thiocyanate Ammonium thiocyanate
Potassium thiocyanate
| OtherCompounds =
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Copper(I) thiocyanate (or cuprous thiocyanate) is a coordination polymer with formula CuSCN. It is an air-stable, white solid used as a precursor for the preparation of other thiocyanate salts.
Structure
At least two polymorphs have been characterized by X-ray crystallography. They both feature copper(I) in a characteristic tetrahedral coordination geometry. The sulfur end of the SCN- ligand is triply bridging so that the coordination sphere for copper is CuS3N.Smith, D. L.; Saunders, V. I. "Preparation and Structure Refinement of the 2H Polytype of beta-Copper(I) Thiocyanate" Acta Crystallographica B, 1982, volume 38, 907-909. {{doi|10.1107/S0567740882004361}}{{cite journal |doi=10.1016/S0020-1693(00)81976-3|title=The Crystal Structure of Copper(I) Thiocyanate and Its Relation to the Crystal Structure of Copper(II) Diammine Dithiocyanate Complex |year=1976 |last1=Kabešová |first1=M. |last2=Dunaj-Jurčo |first2=M. |last3=Serator |first3=M. |last4=Gažo |first4=J. |last5=Garaj |first5=J. |journal=Inorganica Chimica Acta |volume=17 |pages=161–165 }}
Synthesis
Copper(I) thiocyanate forms from the spontaneous decomposition of black copper(II) thiocyanate, releasing thiocyanogen, especially when heated.{{Cite journal|last1=Hunter|first1=J. A.|last2=Massie|first2=W. H. S.|last3=Meiklejohn|first3=J.|last4=Reid|first4=J.|date=1969-01-01|title=Thermal rearrangement in copper(II) thiocyanate|journal=Inorganic and Nuclear Chemistry Letters|volume=5|issue=1|pages=1–4|doi=10.1016/0020-1650(69)80226-6|issn=0020-1650}} It is also formed from copper(II) thiocyanate under water, releasing (among others) thiocyanic acid and the highly poisonous hydrogen cyanide. It is conveniently prepared from relatively dilute solutions of copper(II) in water, such as copper(II) sulphate. To a copper(II) solution sulphurous acid is added and then a soluble thiocyanate is added (preferably slowly, while stirring). Copper(I) thiocyanate is precipitated as a white powder. Alternatively, a thiosulfate solution may be used as a reducing agent.
Double salts
Copper(I) thiocyanate forms one double salt with the group 1 elements, CsCu(SCN)2. The double salt only forms from concentrated solutions of CsSCN, into which CuSCN dissolves. From less concentrated solutions, solid CuSCN separates reflecting its low solubility. When brought together with potassium, sodium or barium thiocyanate, and brought to crystallisation by concentrating the solution, mixed salts will crystallise out. These are not considered true double salts. As with CsCu (SNC)2, copper(I) thiocyanate separates out when these mixed salts are redissolved or their solutions diluted.
Uses
Copper(I) thiocyanate is a hole conductor, a semiconductor with a wide band gap (3.6 eV, therefore transparent to visible and near infrared light).{{cite book|title=Nanostructured Materials|author=Wilde, G.|date=2009|publisher=Elsevier Science|isbn=9780080914237|url=https://books.google.com/books?id=1qnL0qO9KNcC&pg=PA256|page=256|accessdate=14 January 2017}} It is used in photovoltaics in some third-generation cells as a hole transfer layer. It acts as a P-type semiconductor and as a solid-state electrolyte. It is often used in dye-sensitized solar cells. Its hole conductivity is however relatively poor (0.01 S·m−1). This can be improved by various treatments, e.g. exposure to gaseous chlorine or doping with (SCN)2.{{cite book|title=Photochemistry|author1=Albini, A.|author2=Fausto, R.|author3=de Melo, J.S.S.|author4=Maldotti, A.|author5=Clementi, C.|author6=Kalyanasundaram, K.|author7=Johnston, L.J.|author8=Harbron, E.|author9=Misawa, H.|author10=Romani, A.|date=2011|publisher=Royal Society of Chemistry|isbn=9781849731652|url=https://books.google.com/books?id=NJJTW_zU5QUC&pg=PA164|page=164|accessdate=14 January 2017}}
CuSCN with NiO act synergically as a smoke suppressant additive in polyvinyl chloride (PVC).
CuSCN precipitated on carbon support can be used for conversion of aryl halides to aryl thiocyanates.{{cite book|title=Supported Reagents: Preparation, Analysis, and Applications|author1=Clark, J.H.|author2=Kybett, A.P.|author3=Macquarrie, D.J.|date=1992|publisher=Wiley|isbn=9780471187790|url=https://books.google.com/books?id=V7ahxSHqMqMC&pg=PA121|page=121|accessdate=14 January 2017}}
Copper thiocyanate is used in some anti-fouling paints.{{Cite web | url=http://www.copperantifouling.com/copper/ | title=Copper in Antifouling | access-date=2017-04-25 | archive-date=2017-04-27 | archive-url=https://web.archive.org/web/20170427190922/http://www.copperantifouling.com/copper/ | url-status=dead }}{{cite journal | url=https://link.springer.com/article/10.1007/BF02696144 | doi=10.1007/BF02696144 | title=Solubility and toxic effect of the cuprous thiocyanate antifouling pigment on barnacle larvae | date=1997 | last1=Vetere | first1=V. F. | last2=Pérez | first2=M. C. | last3=Romagnoli | first3=R. | last4=Stupak | first4=M. E. | last5=Amo | first5=B. | journal=Journal of Coatings Technology | volume=69 | issue=3 | pages=39–45 }} Advantages compared to cuprous oxide include that the compound is white and a more efficient biocide.
References
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{{Copper compounds}}
{{DEFAULTSORT:Copper(I) thiocyanate}}