Thiol (or Mercaptan, R-SH) Posted on 23rd December 20155th May 2021 by ThePD (The Project Definition) Thiol (or Mercaptan, R-SH) is an organic sulphur compound that contains a carbon-bonded sulfhydryl (R–SH) group. Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window)Click to share on LinkedIn (Opens in new window) Related Posted in Substance and tagged organic. ThePD (The Project Definition) ThePD has been developing the Preferred Project Definitions based on the actual project execution and operation experiences and knowledge with the Project Language, and sharing with you daily basis.