What is "pb3o4"

minium \min"i*um\ (?; 277), n. [L. minium, an Iberian word, the Romans getting all their cinnabar from Spain; cf. Basque armine['a].] (Chem.) A heavy, brilliant red pigment, consisting of an oxide of lead, Pb3O4, obtained by exposing lead or massicot to a gentle and continued heat in the air. It is used as a cement, as a paint, and in the manufacture of flint glass. Called also red lead, lead tetroxide, lead orthoplumbate, mineral orange, mineral red, Paris red, Saturn red, and less definitively, lead oxide.

massicot \mas"si*cot\, n. [F. massicot; E. masticot is a corruption.] (Chem.) Lead monoxide (also called Lead protoxide), PbO, obtained as a yellow amorphous powder, the fused and crystalline form of which is called litharge; lead ocher. It is used as a pigment. It is also called lead oxide yellow, as opposed to red lead, which is lead tetroxide Pb3O4.

Note: Massicot is sometimes used by painters, and also as a drier in the composition of ointments and plasters.