Sodium thiocyanate (sometimes called sodium sulphocyanide) is the
chemical compound
A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...
with the formula NaSCN. This colorless
deliquescent
Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption (chemistry), absorption or adsorption from the surrounding Natural environment, environment, which is usually at normal or room temperature. If water mol ...
salt
In common usage, salt is a mineral composed primarily of sodium chloride (NaCl). When used in food, especially in granulated form, it is more formally called table salt. In the form of a natural crystalline mineral, salt is also known as r ...
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
Sulfur ( American spelling and the preferred IUPAC name) or sulphur ( Commonwealth spelling) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms ...
:
:8 NaCN + S
8 → 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
A laboratory (; ; colloquially lab) is a facility that provides controlled conditions in which scientific or technological research, experiments, and measurement may be performed. Laboratories are found in a variety of settings such as schools ...
as a
test for the presence of
Fe3+ ions.
Applications in chemical synthesis
Sodium thiocyanate is employed to convert
alkyl halides into the corresponding alkylthiocyanates. Treatment of
isopropyl bromide 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). Isothiocyanic acid, typically generated in situ from sodium thiocyanate, adds to
anilines to afford
2-aminobenzothiazoles.
Related compounds
Closely related reagents include
ammonium thiocyanate and
potassium thiocyanate
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.
Uses Ch ...
, which has twice the solubility in water.
Silver thiocyanate may be used as well; the precipitation of insoluble silver halides help simplify
workup.
References
{{Thiocyanates
Sodium compounds
Thiocyanates