Isothiouronium

In organic chemistry, isothiouronium is a functional group with the formula [RSC(NH2)2]+ (R = alkyl, aryl) and is the acid salt of isothiourea.

The CN2S core is planar and the C–N bonds are short.

[1] Salts comprising these cations are typically prepared by alkylation of thiourea: Hydrolysis of isothiouronium salts gives thiols.

[2] Isothiouronium salts in which the sulfur has been alkylated, such as S-methylisothiourea hemisulfate (CAS number: 867-44-7), will convert amines into guanidinium groups.

[5] Chelating resins with isothiouronium groups are used to recover mercury and other noble metals including platinum from solutions.