Lead oxide refers to lead monoxide or "litharge" (PbO), lead tetroxide or "red lead" (Pb 3O 4), and black or "gray" oxide which is a mixture of lead monoxide and metallic lead (an approximate 70:30 ratio) 1 for specific use in the manufacture of lead acid storage batteries. Due to the size of the lead acid battery industry, lead monoxide is the most important commercial compound of lead. Total ...