Sodium thiocyanate

Sodium thiocyanate is the chemical compound with the formula NaSCN. This colourless deliquescent salt is one of the main sources of the thiocyanate anion. As such, it is used as a precursor for the synthesis of pharmaceuticals and other specialty chemicals. Thiocyanate salts are typically prepared by the reaction of cyanide with elemental sulfur:
 * NaCN +  1/8 S8  &rarr;  NaSCN

NaSCN crystallises in an orthorhombic cell. Each Na+ center is surrounded by three sulfur and three nitrogen ligands provided by the triatomic thiocyanate anion.

Applications in chemical synthesis
NaSCN is employed to convert alkyl halides into the corresponding alkylthiocyanates. Closely related reagents include ammonium thiocyanate and potassium thiocyanate, which has twice the solubility in water. Treatment of isopropyl bromide with NaSCN in hot ethanolic solution affords isopropyl thiocyanate (b.p. 146–151 °C). Protonation of NaSCN affords isothiocyanic acid, S=C=NH (pKa = -1.28). This species is generated in situ from NaSCN; it adds to organic amines to afford derivatives of thiourea.