Iron(II) oxide III and forms insoluble hydroxides in water. Iron(II) oxide is used as a pigment. It is FDA-approved for use in cosmetics and it is used in some tattoo inks. It can also be used as a phosphate remover from home aquaria. Iron(II) oxide Iron(II) oxide or ferrous oxide is the inorganic compound with the formula FeO. Its mineral form is known as wüstite. One of several iron oxides, it is a black-colored powder that is sometimes confused with rust, the latter of which consists of hydrated iron(III) oxide (ferric oxide). Iron(II) oxide also refers to a family of related non-stoichiometric
Holmium(III) oxide Holmium(III) oxide Holmium(III) oxide, or holmium oxide is a chemical compound of a rare-earth element holmium and oxygen with the formula HoO. Together with dysprosium(III) oxide (DyO) holmium oxide is one of the most powerfully paramagnetic substances known. The oxide, also called holmia, occurs as a component of the related erbium oxide mineral called erbia. Typically the oxides of the trivalent lanthanides coexist in nature and separation of these components requires specialized methods. Holmium oxide is used in making specialty colored glasses. Glass containing holmium oxide and holmium oxide solutions have a series of sharp optical absorption peaks in the