Potassium thiocyanate
Other names
Potassium sulfocyanate
Potassium isothiocyanate (tautomeric form)
Potassium thiocyanide
Potassium rhodanide
3D model (JSmol)
ECHA InfoCard 100.005.792 Edit this at Wikidata
EC Number
  • 206-370-1
RTECS number
  • XL1925000
  • InChI=1S/CHNS.K/c2-1-3;/h3H;/q;+1/p-1 checkY
  • InChI=1/CHNS.K/c2-1-3;/h3H;/q;+1/p-1
  • C(#N)[S-].[K+]
Molar mass 97.181 g mol−1
Appearance Colorless deliquescent crystals
Odor Odorless
Density 1.886 g/cm3
Melting point 173.2 °C (343.8 °F; 446.3 K)
Boiling point 500 °C (932 °F; 773 K) (decomposes)
177 g/100 mL (0 °C)
217 g/100 mL (20 °C)
Solubility acetone: 21.0 g/100 mL
ethanol: soluble
−48.0·10−6 cm3/mol
GHS labelling:
GHS05: CorrosiveGHS07: Exclamation mark
H302, H312, H318, H319, H332, H412
P261, P264, P270, P271, P273, P280, P301+P312, P302+P352, P304+P312, P304+P340, P305+P351+P338, P310, P312, P322, P330, P337+P313, P363, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
Lethal dose or concentration (LD, LC):
854 mg/kg (oral, rat)[1]
Safety data sheet (SDS) ICSC 1088
Related compounds
Other anions
Potassium cyanate
Potassium cyanide
Other cations
Sodium thiocyanate
Ammonium thiocyanate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Potassium thiocyanate is the chemical compound with the molecular formula KSCN. It is an important salt of the thiocyanate anion, one of the pseudohalides. The compound has a low melting point relative to most other inorganic salts.

Use in chemical synthesis

Aqueous KSCN reacts almost quantitatively with Pb(NO3)2 to give Pb(SCN)2, which has been used to convert acyl chlorides to isothiocyanates.[2]

KSCN converts ethylene carbonate to ethylene sulfide.[3] For this purpose, the KSCN is first melted under vacuum to remove water. In a related reaction, KSCN converts cyclohexene oxide to the corresponding episulfide and KOCN. [4]

KSCN is also the starting product for the synthesis of carbonyl sulfide.

Other uses

Dilute aqueous KSCN is occasionally used for moderately realistic blood effects in film and theater. It can be painted onto a surface or kept as a colorless solution. When in contact with ferric chloride solution (or other solutions containing Fe3+), the product of the reaction is a solution with a blood red colour, due to the formation of the thiocyanatoiron complex ion. Thus this chemical is often used to create the effect of 'stigmata'. Because both solutions are colorless, they can be placed separately on each hand. When the hands are brought into contact, the solutions react and the effect looks remarkably like stigmata.[citation needed]

Similarly, this reaction is used as a test for Fe3+ in the laboratory.


  1. ^ Chambers, Michael. "ChemIDplus - 333-20-0 - ZNNZYHKDIALBAK-UHFFFAOYSA-M - Potassium thiocyanate [NF] - Similar structures search, synonyms, formulas, resource links, and other chemical information". chem.sis.nlm.nih.gov. Retrieved 19 April 2018.
  2. ^ Smith, P. A. S.; Kan, R. O. (1973). "2a-Thiohomophthalimide". Organic Syntheses.; Collective Volume, vol. 5, p. 1051
  3. ^ Searles, S.; Lutz, E. F.; Hays, H. R.; Mortensen, H. E. (1973). "Ethylenesulfide". Organic Syntheses.; Collective Volume, vol. 5, p. 562
  4. ^ van Tamelen, E. E. (1963). "Cyclohexenesulfide". Organic Syntheses.; Collective Volume, vol. 4, p. 232