Terbium monosulfideTerbium monosulfide is a binary inorganic compound of terbium and sulfur with the chemical formula TbS.SynthesisTerbium monosulfide can be synthesised by heating stoichiometric amounts of pure substances in an inert atmosphere:Physical propertiesTerbium monosulfide forms crystals of cubic system, space group Fm3''m'', isomorphous with NaCl.