Science, Tech, Math › Science Thiol Group Definition Share Flipboard Email Print This is the chemical structure of cysteine. The yellow SH on the left hand side is a thiol group. Todd Helmenstine Science Chemistry Chemical Laws Basics Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry in Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate by Anne Marie Helmenstine, Ph.D. Updated March 06, 2017 Definition: A thiol group is a fuctional group containing a sulfur atom bonded to a hydrogen atom. General formula: -SHAlso Known As: sulfanyl group, mercapto groupExamples: The amino acid cysteine contains a thiol group. citecite this article Format mla apa chicago Your Citation Helmenstine, Anne Marie, Ph.D. "Thiol Group Definition." ThoughtCo, Jun. 13, 2014, thoughtco.com/definition-of-thiol-group-605735. Helmenstine, Anne Marie, Ph.D. (2014, June 13). Thiol Group Definition. Retrieved from https://www.thoughtco.com/definition-of-thiol-group-605735 Helmenstine, Anne Marie, Ph.D. "Thiol Group Definition." ThoughtCo. https://www.thoughtco.com/definition-of-thiol-group-605735 (accessed April 20, 2018). copy citation Continue Reading