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Iron(II) oxide or ferrous oxide is the inorganic compound with the formula FeO. Its mineral form is known as wüstite . [ 3 ] [ 4 ] 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).
Simplified diagram of the iron oxide cycle. For chemical reactions, the iron oxide cycle (Fe 3 O 4 /FeO) is the original two-step thermochemical cycle proposed for use for hydrogen production. [1] It is based on the reduction and subsequent oxidation of iron ions, particularly the reduction and oxidation between Fe 3+ and Fe 2+.
Iron plays an important role in the nitrogen cycle, aside from its role as part of the enzymes involved in nitrogen fixation. In anoxic conditions, Fe(II) can donate an electron that is accepted by NO 3 − which is oxidized to several different forms of nitrogen compounds, NO 2 −, N 2 O, N 2, and NH 4 +, while Fe(II) is reduced to Fe(III). [33]
The following chart shows the solubility of various ionic compounds in water at 1 atm pressure and room temperature (approx. 25 °C, 298.15 K). "Soluble" means the ionic compound doesn't precipitate, while "slightly soluble" and "insoluble" mean that a solid will precipitate; "slightly soluble" compounds like calcium sulfate may require heat to precipitate.
Iron is stored in many organisms in the form of ferritin, which is a ferrous oxide encased in a solubilizing protein sheath. [ 10 ] Species of bacteria , including Shewanella oneidensis , Geobacter sulfurreducens and Geobacter metallireducens , use iron oxides as terminal electron acceptors .
The nitrogen cycle is an important process in the ocean as well. While the overall cycle is similar, there are different players [42] and modes of transfer for nitrogen in the ocean. Nitrogen enters the water through the precipitation, runoff, or as N 2 from the atmosphere. Nitrogen cannot be utilized by phytoplankton as N
The formula for magnetite is more accurately written as FeO·Fe 2 O 3 than as Fe 3 O 4. Magnetite is one part FeO and one part Fe 2 O 3, rather than a solid solution of wüstite and hematite. Magnetite is termed a redox buffer because, until all Fe 3+ present in the system is converted to Fe 2+, the oxide mineral assemblage of iron remains ...
Iron(III) oxide is insoluble in water but dissolves readily in strong acid, e.g., hydrochloric and sulfuric acids. It also dissolves well in solutions of chelating agents such as EDTA and oxalic acid. Heating iron(III) oxides with other metal oxides or carbonates yields materials known as ferrates (ferrate (III)): [18] ZnO + Fe 2 O 3 → Zn(FeO ...