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.

Mercaptobenzimidazole
Names
Preferred IUPAC name
1,3-Dihydro-2H-1,3-benzimidazole-2-thione
Identifiers
3D model (JSmol)
ChEMBL
ChemSpider
ECHA InfoCard 100.008.640 Edit this at Wikidata
EC Number
  • 604-756-8
  • 209-502-6
RTECS number
  • DE1050000
UNII
UN number 2811
  • 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
  • C1=CC=C2C(=C1)NC(=S)N2
Properties
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:
GHS07: Exclamation markGHS08: Health hazardGHS09: Environmental hazard
Warning
H302, H332, H361, H373, H410
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).

It is prepared from o-phenylenediamine.[2]

References

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  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.