organophosphate nerve agent - any of a series of nerve agents containing organophosphate compounds first synthesized by German chemists in 1936; in World War II the Germans tested them in concentration camps but not on the battlefield; Iraq is alleged to have used them against Iran and against the Kurds

metal, metallic element - any of several chemical elements that are usually shiny solids that conduct heat or electricity and can be formed into sheets etc.

gadolinite, ytterbite - a mineral that is a source of rare earths; consists of silicates of iron and beryllium and cerium and yttrium and erbium

samarskite - a complex black mineral occuring in pegmatites