noun
1. : any of various acids derived from molybdenum trioxide ; especially : the simplest acid H 2 MoO 4 obtained as white crystals or as the yellow crystalline monohydrate H 2 MoO 4 .H 2 O but known chiefly in the form of salts many of which are unstable and readily form polymolybdates — compare heteropoly acid , phosphomolybdic acid
2.
a. : molybdenum trioxide — not used systematically
b. : ammonium molybdate containing added molybdenum trioxide — called also molybdic acid 85 percent ; not used systematically