Copper(I) thiocyanate

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Copper(I) thiocyanate
Tiotsianat medi(I) (synthesized and photographed by Paliienko Konstantin).jpg
Copper(I) thiocyanate
CuSCN-beta.png
Names
Other names
Cuprous thiocyanate
Identifiers
ChemSpider
ECHA InfoCard 100.012.894 OOjs UI icon edit-ltr-progressive.svg
PubChem CID
UNII
Properties
CuSCN
Molar mass 121.628 g/mol [1]
Appearancewhite powder
Density 2.88 g/cm3 [2]
Melting point 1,084 [1]  °C (1,983 °F; 1,357 K)
8.427·10−7 g/L (20 °C)
1.77×10−13 [3]
-48.0·10−6 cm3/mol
Related compounds
Other anions
Copper(I) iodide, copper(I) cyanide
Other cations
Ammonium thiocyanate
Potassium thiocyanate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

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.

Contents

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. [2] [4]

Synthesis

Copper(I) thiocyanate forms from the spontaneous decomposition of black copper(II) thiocyanate, releasing thiocyanogen, especially when heated. [5] It is also formed from copper(II) thiocyanate under water, releasing (among others) thiocyanic acid and the highly poisonous hydrogen cyanide. [6] 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 [7] ). Copper(I) thiocyanate is precipitated as a white powder. [8] 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. [9] 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. [10]

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). [11] 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. [12]

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. [13]

Copper thiocyanate is used in some anti-fouling paints. [14] [15] Advantages compared to cuprous oxide include that the compound is white and a more efficient biocide.

Related Research Articles

<span class="mw-page-title-main">Iron(III)</span> The element iron in its +3 oxidation state

In chemistry, iron(III) refers to the element iron in its +3 oxidation state. In ionic compounds (salts), such an atom may occur as a separate cation (positive ion) denoted by Fe3+.

<span class="mw-page-title-main">Copper(I) oxide</span> Chemical compound – an oxide of copper with formula Cu2O

Copper(I) oxide or cuprous oxide is the inorganic compound with the formula Cu2O. It is one of the principal oxides of copper, the other being or copper(II) oxide or cupric oxide (CuO). This red-coloured solid is a component of some antifouling paints. The compound can appear either yellow or red, depending on the size of the particles. Copper(I) oxide is found as the reddish mineral cuprite.

<span class="mw-page-title-main">Thiocyanate</span> Ion (S=C=N, charge –1)

Thiocyanate is the anion [SCN]−. It is the conjugate base of thiocyanic acid. Common derivatives include the colourless salts potassium thiocyanate and sodium thiocyanate. Mercury(II) thiocyanate was formerly used in pyrotechnics.

Cuprate loosely refers to a material that can be viewed as containing anionic copper complexes. Examples include tetrachloridocuprate ([CuCl4]2−), the superconductor YBa2Cu3O7, and the organocuprates (e.g., dimethylcuprate [Cu(CH3)2]−). The term cuprates derives from the Latin word for copper, cuprum. The term is mainly used in three contexts: oxide materials, anionic coordination complexes, and anionic organocopper compounds.

<span class="mw-page-title-main">Copper(I) chloride</span> Chemical compound

Copper(I) chloride, commonly called cuprous chloride, is the lower chloride of copper, with the formula CuCl. The substance is a white solid sparingly soluble in water, but very soluble in concentrated hydrochloric acid. Impure samples appear green due to the presence of copper(II) chloride (CuCl2).

The Sandmeyer reaction is a chemical reaction used to synthesize aryl halides from aryl diazonium salts using copper salts as reagents or catalysts. It is an example of a radical-nucleophilic aromatic substitution. The Sandmeyer reaction provides a method through which one can perform unique transformations on benzene, such as halogenation, cyanation, trifluoromethylation, and hydroxylation.

The Ullmann condensation or Ullmann-type reaction is the copper-promoted conversion of aryl halides to aryl ethers, aryl thioethers, aryl nitriles, and aryl amines. These reactions are examples of cross-coupling reactions.

<span class="mw-page-title-main">Diazonium compound</span> Diazonium salts of formula R-N≡N+

Diazonium compounds or diazonium salts are a group of organic compounds sharing a common functional group [R−N+≡N]X− where R can be any organic group, such as an alkyl or an aryl, and X is an inorganic or organic anion, such as a halide.

<span class="mw-page-title-main">Copper(I) iodide</span> Chemical compound

Copper(I) iodide is the inorganic compound with the formula CuI. It is also known as cuprous iodide. It is useful in a variety of applications ranging from organic synthesis to cloud seeding.

<span class="mw-page-title-main">Copper monosulfide</span> Chemical compound

Copper monosulfide is a chemical compound of copper and sulfur. It was initially thought to occur in nature as the dark indigo blue mineral covellite. However, it was later shown to be rather a cuprous compound, formula Cu+3S(S2). CuS is a moderate conductor of electricity. A black colloidal precipitate of CuS is formed when hydrogen sulfide, H2S, is bubbled through solutions of Cu(II) salts. It is one of a number of binary compounds of copper and sulfur (see copper sulfide for an overview of this subject), and has attracted interest because of its potential uses in catalysis and photovoltaics.

<span class="mw-page-title-main">Copper(I) cyanide</span> Chemical compound

Copper(I) cyanide is an inorganic compound with the formula CuCN. This off-white solid occurs in two polymorphs; impure samples can be green due to the presence of Cu(II) impurities. The compound is useful as a catalyst, in electroplating copper, and as a reagent in the preparation of nitriles.

<span class="mw-page-title-main">Mercury(II) thiocyanate</span> Chemical compound

Mercury(II) thiocyanate (Hg(SCN)2) is an inorganic chemical compound, the coordination complex of Hg2+ and the thiocyanate anion. It is a white powder. It will produce a large, winding "snake" when ignited, an effect known as the Pharaoh's serpent.

<span class="mw-page-title-main">Sodium thiocyanate</span> Chemical compound

Sodium thiocyanate (sometimes called sodium sulphocyanide) is the chemical compound with the formula NaSCN. This colorless deliquescent salt is one of the main sources of the thiocyanate anion. As such, it is used as a precursor for the synthesis of pharmaceuticals and other specialty chemicals. Thiocyanate salts are typically prepared by the reaction of cyanide with elemental sulfur:

<span class="mw-page-title-main">Copper(I) fluoride</span> Chemical compound

Copper(I) fluoride or cuprous fluoride is an inorganic compound with the chemical formula CuF. Its existence is uncertain. It was reported in 1933 to have a sphalerite-type crystal structure. Modern textbooks state that CuF is not known, since fluorine is so electronegative that it will always oxidise copper to its +2 oxidation state. Complexes of CuF such as [(Ph3P)3CuF] are, however, known and well characterised.

<span class="mw-page-title-main">Cobalt(II) thiocyanate</span> Chemical compound

Cobalt(II) thiocyanate is an inorganic compound with the formula Co(SCN)2. It is a layered coordination complex and its trihydrate Co(SCN)2(H2O)3 is used in the cobalt thiocyanate test (or Scott test) for detecting cocaine. The test has been responsible for widespread false positives and false convictions.

<span class="mw-page-title-main">Lead(II) thiocyanate</span> Chemical compound

Lead(II) thiocyanate is a compound, more precisely a salt, with the formula Pb(SCN)2. It is a white crystalline solid, but will turn yellow upon exposure to light. It is slightly soluble in water and can be converted to a basic salt (Pb(CNS)2·Pb(OH)2 when boiled. Salt crystals may form upon cooling. Lead thiocyanate can cause lead poisoning if ingested and can adversely react with many substances. It has use in small explosives, matches, and dyeing.

<span class="mw-page-title-main">Tetrakis(acetonitrile)copper(I) hexafluorophosphate</span> Chemical compound

Tetrakis(acetonitrile)copper(I) hexafluorophosphate is a salt with the formula [Cu(CH3CN)4]PF6. It is a colourless solid that is used in the synthesis of other copper complexes. The cation [Cu(CH3CN)4]+ is a well-known example of a transition metal nitrile complex.

Copper(I) nitrate is a proposed inorganic compound with formula of CuNO3. It has not been characterized by X-ray crystallography. It is the focus of one publication, which describes unsuccessful efforts to isolate the compound. Another nonexistent simple copper(I) compound derived from an oxyanion is cuprous perchlorate. On the other hand, cuprous sulfate is known.

<span class="mw-page-title-main">Copper(II) thiocyanate</span> Chemical compound

Copper(II) thiocyanate (or cupric thiocyanate) is a coordination polymer with formula Cu(SCN)2. It is a black solid which slowly decomposes in moist air. It was first reported in 1838 by Carl Ernst Claus and its structure was determined first in 2018.

<span class="mw-page-title-main">Copper compounds</span> Chemical compounds containing copper

Copper forms a rich variety of compounds, usually with oxidation states +1 and +2, which are often called cuprous and cupric, respectively. Copper compounds, whether organic complexes or organometallics, promote or catalyse numerous chemical and biological processes.

References

  1. 1 2 "Properties of Copper(I) thiocyanate". Chemspider. Alfa Aesar 40220. Retrieved 5 January 2016.
  2. 1 2 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
  3. ↑ John Rumble (June 18, 2018). CRC Handbook of Chemistry and Physics (99 ed.). CRC Press. pp. 5–188. ISBN   978-1138561632.
  4. ↑ Kabešová, M.; Dunaj-Jurčo, M.; Serator, M.; Gažo, J.; Garaj, J. (1976). "The Crystal Structure of Copper(I) Thiocyanate and Its Relation to the Crystal Structure of Copper(II) Diammine Dithiocyanate Complex". Inorganica Chimica Acta. 17: 161–165. doi:10.1016/S0020-1693(00)81976-3.
  5. ↑ Hunter, J. A.; Massie, W. H. S.; Meiklejohn, J.; Reid, J. (1969-01-01). "Thermal rearrangement in copper(II) thiocyanate". Inorganic and Nuclear Chemistry Letters. 5 (1): 1–4. doi:10.1016/0020-1650(69)80226-6. ISSN   0020-1650.
  6. ↑ David Tudela (1993). "The Reaction of Copper(II) with Thiocyanate Ions (Letter to the Editor)". Journal of Chemical Education. 70 (2): 174. doi: 10.1021/ed070p174.3 . PDF copy
  7. ↑ Matthew Dick (1969). "Use of cuprous thiocyanate as a short-term continuous marker for faeces". Gut. 10 (5): 408–412 (408). doi:10.1136/gut.10.5.408. PMC   1552857 . PMID   5771673. PDF copy
  8. ↑ Reece H. Vallance, Douglas F. Twiss and Miss Annie R. Russell (1931). J. Newton Friend (ed.). A text-book of inorganic chemistry, volume VII, part II. Charles Griffin & Company Ltd. p. 282.
  9. ↑ H.L.Wells (1902). "On some double and triple thiocyanates". American Chemical Journal. 28: 245–284 (263).
  10. ↑ Herbert E. Williams (1915). The chemistry of cyanogen compounds. J. & A. Churchill, London. pp. 202–203.
  11. ↑ Wilde, G. (2009). Nanostructured Materials. Elsevier Science. p. 256. ISBN   9780080914237 . Retrieved 14 January 2017.
  12. ↑ Albini, A.; Fausto, R.; de Melo, J.S.S.; Maldotti, A.; Clementi, C.; Kalyanasundaram, K.; Johnston, L.J.; Harbron, E.; Misawa, H.; Romani, A. (2011). Photochemistry. Royal Society of Chemistry. p. 164. ISBN   9781849731652 . Retrieved 14 January 2017.
  13. ↑ Clark, J.H.; Kybett, A.P.; Macquarrie, D.J. (1992). Supported Reagents: Preparation, Analysis, and Applications. Wiley. p. 121. ISBN   9780471187790 . Retrieved 14 January 2017.
  14. ↑ "Copper in Antifouling".
  15. ↑ V.F. Vetere et al, "Solubility and Toxic Effect of the Cuprous Thiocyanate Antifouling Pigment on Barnacle Larvae", Journal of Coatings Technology, 69:39 (March 1997)
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