Mercaptobenzimidazole

Mercaptobenzimidazole
Names
	Preferred IUPAC name 1,3-Dihydro-2H-1,3-benzimidazole-2-thione
Identifiers
CAS Number	583-39-1;
3D model (JSmol)	Interactive image;
ChEMBL	ChEMBL70141;
ChemSpider	616466;
ECHA InfoCard	100.008.640
EC Number	604-756-8; 209-502-6;
PubChem CID	707035;
RTECS number	DE1050000;
UNII	619CVM6HOK;
UN number	2811
CompTox Dashboard (EPA)	DTXSID9025536 ;
	InChI InChI=1S/C7H6N2S/c10-7-8-5-3-1-2-4-6(5)9-7/h1-4H,(H2,8,9,10) Key: YHMYGUUIMTVXNW-UHFFFAOYSA-N;
	SMILES C1=CC=C2C(=C1)NC(=S)N2;
Properties
Chemical formula	C7H6N2S
Molar mass	150.20 g·mol−1
Appearance	white solid
Density	1.42 g/cm3
Melting point	298 °C (568 °F; 571 K)
Hazards
	GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H302, H332, H361, H373, H410
Precautionary statements	P201, P202, P260, P261, P264, P270, P271, P273, P281, P301+P312, P304+P312, P304+P340, P308+P313, P312, P314, P330, P391, P405, P501
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Mercaptobenzimidazole is the organosulfur compound with the formula C₆H₄(NH)₂C=S. It is the mercaptan of benzimidazole. It is a white solid that has been investigated as a corrosion inhibitor. The name is a misnomer because the compound is a thiourea, characterized with a short C=S bond length of 169 pm.^[1] A similar situation applies to 2-mercaptoimidazole, which is also a thiourea properly called 2-imidazolidinethione and mercaptobenzothiazole, which is also a thioamide.

It is prepared from o-phenylenediamine.^[2]

References

^ Form, G. R.; Raper, E. S.; Downie, T. C. (1976). "The crystal and molecular structure of 2-mercaptobenzimidazole". Acta Crystallographica Section B: Structural Crystallography and Crystal Chemistry. 32 (2): 345–348. doi:10.1107/S0567740876003026.
^ VanAllan, J. A.; Deacon, B. D. (1950). "2-Mercaptobenzimidazole". Organic Syntheses. 30: 56. doi:10.15227/orgsyn.030.0056.

[1] Form, G. R.; Raper, E. S.; Downie, T. C. (1976). "The crystal and molecular structure of 2-mercaptobenzimidazole". Acta Crystallographica Section B: Structural Crystallography and Crystal Chemistry. 32 (2): 345–348. doi:10.1107/S0567740876003026.

[2] VanAllan, J. A.; Deacon, B. D. (1950). "2-Mercaptobenzimidazole". Organic Syntheses. 30: 56. doi:10.15227/orgsyn.030.0056.

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