What Is a Thiol Group?

Definition and Examples

This is the chemical structure of cysteine.
This is the chemical structure of cysteine. The yellow SH on the left hand side is a thiol group. Todd Helmenstine
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Anne Marie Helmenstine, Ph.D.
Chemistry Expert
  • Ph.D., Biomedical Sciences, University of Tennessee at Knoxville
  • B.A., Physics and Mathematics, Hastings College
Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels.
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Anne Marie Helmenstine, Ph.D.
Updated May 14, 2018

Definition: A thiol group is a fuctional group containing a sulfur atom bonded to a hydrogen atom. General formula: -SH

Also Known As: sulfanyl group, mercapto group

Examples: The amino acid cysteine contains a thiol group.

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Helmenstine, Anne Marie, Ph.D. "What Is a Thiol Group?" ThoughtCo, Aug. 25, 2020, thoughtco.com/definition-of-thiol-group-605735. Helmenstine, Anne Marie, Ph.D. (2020, August 25). What Is a Thiol Group? Retrieved from https://www.thoughtco.com/definition-of-thiol-group-605735 Helmenstine, Anne Marie, Ph.D. "What Is a Thiol Group?" ThoughtCo. https://www.thoughtco.com/definition-of-thiol-group-605735 (accessed September 25, 2021).