Silver thiocyanate
Silver thiocyanate is the silver salt of thiocyanic acid with the formula AgSCN. Silver thiocyanate appears as a white crystalline powder. It is very commonly used in the synthesis of silver nanoparticles. Additionally, studies have found silver nanoparticles to be present in saliva present during the entire digestive process of silver nitrate. Silver thiocyanate is slightly soluble in water, with a solubility of 1.68 x 10−4 g/L. It is insoluble in ethanol, acetone, and acid.

Structure
AgSCN is monoclinic with 8 molecules per unit cell. Each SCN− group has an almost linear molecular geometry, with bond angle 179.6(5)°. Weak Ag—Ag interactions of length 0.3249(2) nm to 0.3338(2) nm are present in the structure.

Production

Solution Reaction 
Silver thiocyanate has been commonly produced by the reaction between silver nitrate and potassium thiocyanate.

AgNO3 + KSCN -> KNO3 + AgSCN

Ion-Exchange Route 
Silver thiocyanate may be formed via an ion exchange reaction. In this double displacement reaction, silver nitrate and ammonium thiocyanate are dissolved in distilled water to produce silver thiocyanate and ammonium nitrate.

AgNO3 + NH4SCN -> NH4 NO3 + AgSCN

Additionally, silver thiocyanate can be formed through the double displacement reaction between ammonium thiocyanate and silver chloride to form a precipitate of silver thiocyanate.

AgCl + NH4SCN -> NH4 Cl + AgSCN

Uses 
The most common use of silver thiocyanate is as a silver nanoparticle. Silver thiocyanate nanoparticles have been found in saliva throughout the entire artificial digestion of silver nitrate. The nanoparticles can also be used as good ion conductors.

Silver thiocyanate has also been used to absorb uv-visible light at values less than 500 nm. At longer wavelengths, silver thiocyanate has been found to have good photocatalytic properties.

Characterization 
Upon production, silver thiocyanate can be characterized through a wide range of techniques: x-ray powder diffraction (XRD), x-ray photoelectron spectroscopy (XPS), Raman Spectroscopy, ultraviolet photoelectron spectroscopy (UPS), and thermogravimetric analysis (TGA).

Safety 
Silver thiocyanate is an irritant to the skin and eyes and is additionally acutely toxic when inhaled dermally or orally. It is sensitive when exposed to the skin as well as toxic to specific organs when singley exposed. Silver thiocyanate is both acutely and chronically hazardous to the aquatic environment.

References

Thiocyanates
Silver compounds