Sodium thiocyanate

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 of pharmaceuticals and other specialty chemicals.^[2] Thiocyanate salts are typically prepared by the reaction of cyanide with elemental sulfur:

8 NaCN + S₈ → 8 NaSCN

Sodium thiocyanate

The sodium cation The thiocyanate anion (space-filling model)
Names
IUPAC name Sodium thiocyanate
Other names Sodium rhodanide Sodium sulfocyanate Sodium rhodanate Thiocyanic acid, sodium salt
Identifiers
CAS Number	540-72-7 Y
3D model (JSmol)	Interactive image
Beilstein Reference	3594965
ChEBI	CHEBI:30952 Y
ChEMBL	ChEMBL1644028 Y ChEMBL84336 Y ChEMBL1078613 Y
ChemSpider	10443 Y
ECHA InfoCard	100.007.960
EC Number	208-754-4
Gmelin Reference	1249825
PubChem CID	516871
RTECS number	XL2275000
UNII	5W0K9HKA05 Y
CompTox Dashboard (EPA)	DTXSID4021343
InChI InChI=1S/CHNS.Na/c2-1-3;/h3H;/q;+1/p-1 Y Key: VGTPCRGMBIAPIM-UHFFFAOYSA-M Y InChI=1S/CHNS.Na/c2-1-3;/h3H;/q;+1/p-1 Key: VGTPCRGMBIAPIM-REWHXWOFAB Key: VGTPCRGMBIAPIM-UHFFFAOYSA-M
SMILES [Na+].[S-]C#N
Properties
Chemical formula	NaSCN
Molar mass	81.072 g/mol
Appearance	deliquescent colorless crystals
Density	1.735 g/cm3
Melting point	287 °C (549 °F; 560 K)
Boiling point	307 °C (585 °F; 580 K) decomposes
Solubility in water	139 g/100 mL (21 °C) 225 g/100 mL (100 °C)
Solubility	soluble in acetone, alcohols, ammonia, SO2
Acidity (pKa)	−1.28
Refractive index (nD)	1.545
Structure
Crystal structure	orthorhombic
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H302, H312, H332, H412
Precautionary statements	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)	2 0 0
Lethal dose or concentration (LD, LC):
LD50 (median dose)	764 mg/kg (oral, rat)[1]
Safety data sheet (SDS)	ICSC 0675
Related compounds
Other anions	Sodium cyanate Sodium cyanide
Other cations	Lithium thiocyanate Potassium thiocyanate Ammonium thiocyanate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

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.^[3] 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 halides into the corresponding alkylthiocyanates. Treatment of isopropyl bromide with sodium thiocyanate in a hot ethanolic solution affords isopropyl thiocyanate.^[4] Protonation of sodium thiocyanate affords isothiocyanic acid, S=C=NH (pK_a = −1.28).^[5] Isothiocyanic acid, typically generated in situ from sodium thiocyanate, adds to anilines to afford 2-aminobenzothiazoles.^[6]

Related compounds

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.