Black Iron Oxide
Black Iron Oxide Black Iron Oxide is the chemical compound with formula Fe 3 O 4 . It occurs in nature as the mineral magnetite . It is one of a number of iron oxides , the others being iron(II) oxide (FeO), which is rare, and iron(III) oxide (Fe 2 O 3 ) also known as hematite . It contains both Fe 2+ and Fe 3+ ions and is sometimes formulated as FeO ∙ Fe 2 O 3 . This iron oxide is encountered in the laboratory as a black powder. It exhibits permanent magnetism and is ferrimagnetic , but is sometimes incorrectly described as ferromagnetic . [3] Its most extensive use is as a black pigment. For this purpose, it is synthesised rather than being extracted from the naturally occurring mineral as the particle size and shape can be varied by the method of production. [4] Black Iron Oxide Preparation Under anaerobic conditions, ferrous hydroxide (Fe(OH) 2 ) can be oxidized by water to form magnetite and molecular hydrogen . This process is described by the Schikorr...