Thiocyanic acid

Thiocyanic acid[1]
Other names

Hydrogen thiocyanate; Sulfocyanic acid; Sulfocyanide
Identifiers
CAS number 463-56-9 Y
PubChem 781
ChemSpider 760 Y
ChEBI CHEBI:29200 N
ChEMBL CHEMBL84336 Y
Jmol-3D images Image 1
Properties
Molecular formula CHNS
Molar mass 59.09 g mol−1
Solubility in water Miscible
Hazards
R-phrases R20/21/22 R32 R52/53
S-phrases (S2) S13 S61
 N (verify) (what is: Y/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Thiocyanic acid is a chemical compound with the formula HSCN that exists as a mixture with the isomeric compound isothiocyanic acid (HNCS).[2] It is the sulfur analog of cyanic acid (HOCN).

It is a weak acid, bordering on strong, with a pKa of 1.1 at 20°C and extrapolated to zero ionic strength[3].

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.[4]

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

  1. ^ Merck Index, 11th Edition, 9257.
  2. ^ Holleman, A. F.; Wiberg, E. Inorganic Chemistry Academic Press: San Diego, 2001. ISBN 0-12-352651-5.
  3. ^ Martell, A. E.; Smith, R. M.; Motelaitis, R. J. NIST Database 46 National Institute of Standards and Technology: Gaithersburg, MD, 2001.
  4. ^ 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.