Sodium thiocyanate (sometimes called sodium sulphocyanide) is the chemical compound with the formula NaSCN. This colorless deliquescent salt is one of the main sources of the thiocyanate anion. As such, it is used as a precursor for the

synthesis Synthesis or synthesize may refer to: Science Chemistry and biochemistry *Chemical synthesis, the execution of chemical reactions to form a more complex molecule from chemical precursors ** Organic synthesis, the chemical synthesis of organ ...

of pharmaceuticals and other specialty chemicals. Thiocyanate salts are typically prepared by the reaction of

cyanide Cyanide is a naturally occurring, rapidly acting, toxic chemical that can exist in many different forms. In chemistry, a cyanide () is a chemical compound that contains a functional group. This group, known as the cyano group, consists of a ...

with elemental

sulfur Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula ...

: :8 NaCN + S₈ → 8 NaSCN Sodium thiocyanate crystallizes in an orthorhombic cell. Each Na⁺ center is surrounded by three sulfur and three nitrogen ligands provided by the triatomic thiocyanate anion. It is commonly used in the laboratory as a test for the presence of Fe³⁺ ions.

Applications in chemical synthesis

Sodium thiocyanate is employed to convert alkyl

halide In chemistry, a halide (rarely halogenide) is a binary chemical compound, of which one part is a halogen atom and the other part is an element or radical that is less electronegative (or more electropositive) than the halogen, to make a fluor ...

s into the corresponding alkylthiocyanates. Closely related reagents include ammonium thiocyanate and potassium thiocyanate, which has twice the solubility in water. Silver thiocyanate may be used as well; the precipitation of insoluble silver halides help simplify workup. Treatment of

isopropyl bromide 2-Bromopropane, also known as isopropyl bromide and 2-propyl bromide, is the halogenated hydrocarbon with the formula CH3CHBrCH3. It is a colorless liquid. It is used for introducing the isopropyl functional group in organic synthesis. 2-Bromopropa ...

with sodium thiocyanate in a hot ethanolic solution affords isopropyl thiocyanate. Protonation of sodium thiocyanate affords isothiocyanic acid, S=C=NH (pK_a = −1.28). This species is generated in situ from sodium thiocyanate; it adds to organic amines to afford derivatives of thiourea.

References

{{Thiocyanates Sodium compounds Thiocyanates