Thiocyanic acid
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| Names | |||
|---|---|---|---|
| IUPAC name
Nitridosulfanidocarbon[2] | |||
Other names
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| Identifiers | |||
463-56-9  | |||
| 3DMet | B00344 | ||
| ChEBI | CHEBI:29200 | ||
| ChEMBL | ChEMBL84336 | ||
| ChemSpider | 760 | ||
| EC Number | 207-337-4 | ||
| 25178 | |||
| Jmol interactive 3D | Image | ||
| KEGG | C01755  | ||
| MeSH | thiocyanic+acid | ||
| PubChem | 781 | ||
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| Properties | |||
| CHNS | |||
| Molar mass | 59.09 g·mol−1 | ||
| Appearance | colorless, oily liquid | ||
| Odor | pungent | ||
| Density | 2.04 g/cm3 | ||
| Melting point | 5 °C (41 °F; 278 K) | ||
| Miscible | |||
| Solubility | soluble in ethanol, diethyl ether | ||
| log P | 0.429 | ||
| Acidity (pKa) | 0.926 | ||
| Basicity (pKb) | 13.071 | ||
| Hazards | |||
| EU classification (DSD) |
 Xn | ||
| R-phrases | R20/21/22, R32, R52/53 | ||
| S-phrases | (S2), S13 | ||
| Related compounds | |||
| Related alkanenitriles |
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| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |||
| verify (what is ?) | |||
| Infobox references | |||
Thiocyanic acid is a chemical compound with the formula HSCN which exists as a tautomer with isothiocyanic acid (HNCS).[3] The iso- form tends to dominate with the material being about 95% isothiocyanic acid in the vapor phase.[4]
Tautomerism between thiocyanic acid (left) and isothiocyanic acid (right)
It is a weak acid, bordering on strong, with a pKa of 1.1 at 20 °C and extrapolated to zero ionic strength.[5]
HSCN is predicted to have a triple bond between carbon and nitrogen. It has been observed spectroscopically but has not been isolated as a pure substance.[6]
The salts and esters of thiocyanic acid are known as thiocyanates. The salts are composed of the thiocyanate ion (−SCN) and a suitable metal cation (e.g., potassium thiocyanate, KSCN). The esters of thiocyanic acid have the general structure R-SCN.
References
- ↑ Merck Index, 11th Edition, 9257.
- ↑ "thiocyanic acid (CHEBI:29200)". Chemical Entities of Biological Interest. USA: European Bioinformatics Institute. 18 October 2009. Main. Retrieved 5 June 2012.
- ↑ Holleman, A. F.; Wiberg, E. Inorganic Chemistry Academic Press: San Diego, 2001. ISBN 0-12-352651-5.
- ↑ Beard, C. I.; Dailey, B. P. (1950). "The Structure and Dipole Moment of Isothiocyanic Acid". The Journal of Chemical Physics 18 (11): 1437. doi:10.1063/1.1747507.
- ↑ Martell, A. E.; Smith, R. M.; Motelaitis, R. J. NIST Database 46 National Institute of Standards and Technology: Gaithersburg, MD, 2001.
- ↑ Wierzejewska, M.; Mielke, Z. (2001). "Photolysis of Isothiocyanic Acid HNCS in Low-Temperature Matrices. Infrared Detection of HSCN and HSNC Isomers". Chemical Physics Letters 349: 227–234. doi:10.1016/S0009-2614(01)01180-0.
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