Thiosemicarbazide

Thiosemicarbazide is the chemical compound with the formula H₂NC(S)NHNH₂. A white, odorless solid, it is related to thiourea (H₂NC(S)NH₂) by the insertion of an NH center. They are commonly used as ligands for transition metals.^[2] Many thiosemicarbazides are known. These feature an organic substituent in place of one or more H's of the parent molecule. 4-Methyl-3-thiosemicarbazide is a simple example.

Thiosemicarbazide

Names
Preferred IUPAC name Hydrazinecarbothioamide[1]
Other names N-Aminothiourea, Aminothiourea
Identifiers
CAS Number	79-19-6
3D model (JSmol)	Interactive image
ChEMBL	ChEMBL256250
ChemSpider	2005980
ECHA InfoCard	100.001.077
EC Number	201-184-7
PubChem CID	2723789
UNII	6056O8W6ET
UN number	2811 2771
CompTox Dashboard (EPA)	DTXSID9021346
InChI InChI=1S/CH5N3S/c2-1(5)4-3/h3H2,(H3,2,4,5) Key: BRWIZMBXBAOCCF-UHFFFAOYSA-N
SMILES C(=S)(N)NN
Properties
Chemical formula	CH5N3S
Molar mass	91.13 g·mol−1
Appearance	white solid
Density	1.465 g/cm3
Melting point	183 °C (361 °F; 456 K)
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H300, H412
Precautionary statements	P264, P270, P273, P301+P310, P321, P330, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

According to X-ray crystallography, the CSN₃ core of the molecule is almost planar as are the three H atoms nearest the thiocarbonyl group.^[3] This can be explained by models of electron delocalisation.

Reactions

Thiosemicarbazides are precursors to thiosemicarbazones. They are precursors to heterocycles.^[4] Formylation of thiosemicarbazide provides access to triazole.^[5]