Copper(I) thiocyanate
| Names | |
|---|---|
| Other names
Cuprous thiocyanate | |
| Identifiers | |
| 1111-67-7 | |
| ChemSpider | 55204 |
| PubChem | 24857968 |
| Properties | |
| CuSCN | |
| Molar mass | 121.628 g/mol[1] |
| Appearance | white powder |
| Density | 2.84 g/cm3[1] |
| Melting point | 1,084[1] °C (1,983 °F; 1,357 K) |
| 8.427·10-7 g/l (20 °C) | |
| Related compounds | |
| Other anions |
Ammonium thiocyanate Potassium thiocyanate |
| Other cations |
Copper(I) iodide |
| Related compounds |
Thiocyanic acid Thiocyanogen |
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| Infobox references | |
Copper(I) thiocyanate (or cuprous thiocyanate) is a copper compound with formula CuSCN. It can be stored without precautions, making it a convenient starting material for the preparation of other thiocyanate salts through double decomposition.
Properties
Copper(I) thiocyanate is white solid which is stable in air under standard conditions. It is non-hygroscopic.
Synthesis
Copper(I) thiocyanate forms from the spontaneous decomposition of dry black copper(II) thiocyanate, releasing thiocyanogen, especially when heated. It is also formed from copper(II) thiocyanate under water, releasing (among others) thiocyanic acid and the highly poisonous hydrogen cyanide.[2]
It is conveniently prepared from 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[3]). Copper(I) thiocyanate is precipitated as a white powder.[4] 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 CuSCN separates out due to its low solubility. With potassium and ammonium, no double thiocyanates could be prepared.[5] 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.[6]
References
- 1 2 3 "Properties of Copper(I) thiocyanate". Chemspider. Alfa Aesar 40220. Retrieved 5 January 2016.
- ↑ 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
- ↑ Matthew Dick (1969). "Use of cuprous thiocyanate as a short-term continuous marker for faeces". Gut 10: 408–412 (408). doi:10.1136/gut.10.5.408.PDF copy
- ↑ 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.
- ↑ H.L.Wells (1902). "On some double and triple thiocyanates". American Chemical Journal 28: 245–284 (263).
- ↑ Herbert E. Williams (1915). The chemistry of cyanogen compounds. J. & A. Churchill, London. pp. 202–203.
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