Plural of mercaptan . It is the generic name that in chemistry receive a group of natural gaseous substances with unpleasant odors. They are organic compounds that possess in their molecules one sulfur atom and one hydrogen atom. They are also called thiols, Tiol group or Hydroxyl group. They are natural gaseous substances released by decaying organic matter. They have a strong smell of rotten cabbage. They are sulfide compounds that can be used as flavorings of home natural gas, to be able to detect it, as well as additive in the fuel for aircraft. They are flammable, strong odor and are non-toxic. It can be found in blood, brain and animal tissues. They are usually released along with faeces.