VG (IUPAC name: O,O-diethyl S-[2-(diethylamino)ethyl] phosphorothioate) (also called amiton or Tetram) is a "V-series" nerve agent chemically similar to the better-known VX nerve agent. Tetram was the proposed trade name for the substance and amiton its ISO common name when it was tested as an acaricide by ICI in the 1950s. It is now only of historic interest as the first member of the V-series.