c2h5sh

Mercaptan \Mer*cap"tan\, n. [F., fr. NL. mercurius mercury + L.
   captans, p. pr. of captare to seize, v. intens. fr. capere.]
   (Chem.)
   Any one of series of compounds having an {-SH} radical
   attached to a carbon atom, also considered as hydrosulphides
   of alcohol radicals, in composition resembling the alcohols,
   but containing sulphur in place of oxygen, and hence called
   also the {sulphur alcohols}. In general, they are colorless
   liquids having a strong, repulsive, garlic odor. The name is
   specifically applied to ethyl mercaptan, {C2H5SH}. So called
   from its avidity for mercury, and other metals.
   [1913 Webster]
    

ethyl mercaptan \eth"yl mer*cap"tan\, (Chem.)
   A gaseous substance ({C2H5.SH}) used as an odorant in natural
   gas and propane to facilitate detection and serve as a
   warning of leaks.
   [PJC]