Editing Group 7 element (section)

==== Manganese ====

[[File:Manganese(IV)_oxide.jpg|thumb|right|Manganese(IV) oxide]]

Manganese forms a variety of oxides: [[Manganese(II) oxide|MnO]], [[Manganese(II,III) oxide|Mn<sub>3</sub>O<sub>4</sub>]], [[Manganese(III) oxide|Mn<sub>2</sub>O<sub>3</sub>]], [[Manganese dioxide|MnO<sub>2</sub>]], MnO<sub>3</sub> and [[Manganese heptoxide|Mn<sub>2</sub>O<sub>7</sub>]]. Manganese(II) oxide is an inorganic compound that forms green crystals. Like many monoxides, MnO adopts the [[Cubic crystal system#Rock-salt structure|rock salt structure]], where cations and anions are both octahedrally coordinated. Also like many oxides, manganese(II) oxide is often [[nonstoichiometric]]: its composition can vary from MnO to MnO<sub>1.045</sub>.<ref name="G&W" />
Manganese(II,III) oxide is formed when any manganese oxide is heated in air above 1000&nbsp;°C.<ref name="G&W" /> Considerable research has centred on producing nanocrystalline Mn<sub>3</sub>O<sub>4</sub> and various syntheses that involve oxidation of Mn<sup>II</sup> or reduction of Mn<sup>VI</sup>.<ref>Hausmannite Mn<sub>3</sub>O<sub>4</sub> nanorods: synthesis, characterization and magnetic properties Jin Du et al.  Nanotechnology, (2006),17 4923-4928, {{doi| 10.1088/0957-4484/17/19/024}}</ref><ref>One-step synthesis of Mn<sub>3</sub>O<sub>4</sub> nanoparticles: Structural and magnetic study Vázquez-Olmos A.,  Redón R, Rodríguez-Gattorno G., Mata-Zamora M.E., Morales-Leal F, Fernández-Osorio A.L, Saniger J.M.   Journal of Colloid and Interface Science, 291, 1, (2005), 175-180 {{doi|10.1016/j.jcis.2005.05.005}}</ref><ref>{{Cite journal |last1=Sun |first1=Xiaoming |last2=Liu |first2=Junfeng |last3=Li |first3=Yadong |date=2006-02-20 |title=Use of Carbonaceous Polysaccharide Microspheres as Templates for Fabricating Metal Oxide Hollow Spheres |url=https://onlinelibrary.wiley.com/doi/10.1002/chem.200500660 |journal=Chemistry - A European Journal |language=en |volume=12 |issue=7 |pages=2039–2047 |doi=10.1002/chem.200500660 |pmid=16374888 |issn=0947-6539|url-access=subscription }}</ref> Manganese(III) oxide is unlike many other transition metal oxides in that it does not adopt the [[corundum]] ([[aluminium oxide|Al<sub>2</sub>O<sub>3</sub>]]) structure.<ref name="G&W" /> Two forms are generally recognized, α-Mn<sub>2</sub>O<sub>3</sub> and γ-Mn<sub>2</sub>O<sub>3</sub>,<ref name = "Wells">Wells A.F. (1984) ''Structural Inorganic Chemistry'' 5th edition Oxford Science Publications {{ISBN|0-19-855370-6}}</ref> although a high pressure form with the CaIrO<sub>3</sub> structure has been reported too.<ref>High Pressure Phase transition in Mn<sub>2</sub>O<sub>3</sub> to the CaIrO<sub>3</sub>-type Phase Santillan, J.; Shim, S. American Geophysical Union, Fall Meeting 2005, abstract #MR23B-0050</ref> Manganese(IV) oxide is a blackish or brown solid occurs naturally as the mineral [[pyrolusite]], which is the main ore of manganese and a component of [[manganese nodule]]s. The principal use for MnO<sub>2</sub> is for dry-cell [[battery (electricity)|batteries]], such as the [[alkaline battery]] and the [[zinc–carbon battery]].<ref name="G&W" /> Manganese(VII) oxide is dark green in its [[crystalline]] form. The liquid is green by reflected light and red by transmitted light.<ref name=brauer>{{cite book|author=H. Lux|chapter=Manganese(VII) Oxide|title=Handbook of Preparative Inorganic Chemistry, 2nd Ed. |editor=G. Brauer|publisher=Academic Press|year=1963|place=NY, NY|volume=1|pages=1459–1460}}</ref> It is soluble in [[carbon tetrachloride]], and decomposes when in contact with water.