Potassium Thiocyanate - KSCN

What is Potassium Thiocyanate?

Potassium thiocyanate is a chemical compound that contains potassium, sulfur, carbon, and nitrogen atoms with the formula KSCN. It is formed by the fusion of sulfur with potassium cyanide, extraction with hot aqueous alcohol, evaporating and cooling.

Potassium thiocyanate occurs as colourless, transparent prismatic crystals that are hygroscopic. It is odourless and has a cooling, saline taste. Alcoholic solution of potassium thiocyanate was shaken up with an acid soil a red colour developed, somewhat in proportion to the acidity of the soil. Therefore, potassium thiocyanate can be used to test the acidity of the soil.

Other names – Potassium rhodanate, potassium rhodanide

Table of Contents

Properties of Potassium Thiocyanate

KSCN Potassium Thiocyanate
Density 1.89 g/cm³
Molecular Weight/ Molar Mass 97.181 g/mol
Boiling Point 500 °C
Melting Point 173 °C
Chemical Formula KSCN

Potassium Thiocyanate Structure – KSCN

Potassium Thiocyanate Structure

Physical Properties of Potassium Thiocyanate – KSCN

Odour Odourless
Appearance Colourless deliquescent crystals
Covalently-Bonded Unit 2
Heat capacity 298.15 K, J/mol·K
Complexity 34.5
Solubility 177 g/100 mL (soluble in water)

Chemical Properties of Potassium Thiocyanate – KSCN

Potassium thiocyanate reacts with iron(III) nitrate forms iron(III) thiocyanate, nitric acid and potassium oxide.

3H2O + 2Fe(NO3)3 + 6KSCN → 2Fe(SCN)3 + 3K2O + 6HNO3

Potassium thiocyanate reacts with iron chloride forming Iron(III) Thiocyanate and potassium chloride.

FeCl3 + 3KSCN → Fe(SCN)3 + 3KCl

Uses of Potassium Thiocyanate – KSCN

  • Used in conjunction with ferric chloride volumetric solution, a red compound is produced at the endpoint.
  • Used in cumbersome, to be carefully followed with blood tests. Overdose may lead to a serious intoxication and blood dyscrasias.
  • Used in the laboratory as a sensitive reagent for the iron ion and with silver nitrate solution for the titrimetric estimation of halides.
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