Manganese(II) oxide: Difference between revisions

| Watchedfields = changed

| verifiedrevid = 431313293

| ImageFile = Manganese(II)-oxide-xtal-3D-SF.png

| ImageSize =

| ImageName = Manganese(II) oxide

| IUPACName = Manganese(II) oxide

| OtherNames = Manganous oxide<br/>[[Manganosite]]<br/>manganese monoxide<br/>oxomanganese

| Section1 = {{Chembox Identifiers

| CASNo_Ref = {{cascite|correct|CAS}}

| CASNo = 1344-43-0

| UNII_Ref = {{fdacite|correct|FDA}}

| UNII = 64J2OA7MH3

| PubChem = 14940

| SMILES = [Mn+2].[O-2]

| RTECS = OP0900000

| Section2 = {{Chembox Properties

| Formula = MnO

| MolarMass = 70.9374 g/mol

| Appearance = green crystals or powder

| Density = 5.43 g/cm³

| MeltingPtC = 1945

| BoilingPt =

| Solubility = insoluble

| SolubleOther = soluble in acid

| RefractIndex = 2.16

| MagSus = +4850.0·10⁻⁶ cm³/mol

| Section3 = {{Chembox Structure

| CrystalStruct = [[Halite]] (cubic), [[Pearson symbol|cF8]]

| SpaceGroup = Fm<u style="text-decoration:overline">3</u>m, No. 225

| Coordination = Octahedral (Mn²⁺); octahedral (O²⁻)

| LattConst_a =

| Section4 = {{Chembox Thermochemistry

| DeltaHf = −385&nbsp;kJ·mol⁻¹<ref name=b1>{{cite book| author = Zumdahl, Steven S.|title =Chemical Principles 6th Ed.| publisher = Houghton Mifflin Company| year = 2009| isbn = 978-0-618-94690-7|page=A22}}</ref>

| Entropy = 60&nbsp;J·mol⁻¹·K⁻¹<ref name=b1/>

}}

| Section7 = {{Chembox Hazards

| ExternalSDS =

| MainHazards =

| NFPA-H = 1

| NFPA-F = 0

| NFPA-R = 0

| NFPA-S =

| FlashPt = Non-flammable

| LD50 =

| PEL =

| Section8 = {{Chembox Related

| OtherAnions = [[Manganese(II) fluoride]]<br/>[[Manganese(II) sulfide]]<br/>[[Manganese(II) selenide]]<br/>[[Manganese(II) telluride]]

| OtherCations = [[Iron(II) oxide]]

| OtherFunction = [[Manganese(II,III) oxide]]<br/>[[Manganese(III) oxide]]<br/>[[Manganese dioxide]]<br/>[[Manganese heptoxide]]

| OtherFunction_label = [[manganese]] [[oxide]]s

'''Manganese(II) oxide''' is an [[inorganic compound]] with [[chemical formula]] MnO.<ref name=Reidies>Arno H. Reidies "Manganese Compounds" Ullmann's Encyclopedia of Chemical Technology 2007; Wiley-VCH, Weinheim. {{doi|10.1002/14356007.a16_123}}</ref> It forms green crystals. The compound is produced on a large scale as a component of [[fertilizer]]s and [[food additives]].

== Structure, stoichiometry, reactivity==

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_1.045.<ref name = "Greenwood">{{Greenwood&Earnshaw2nd}}</ref>

Below 118 K MnO is [[Antiferromagnetism|antiferromagnetic]].<ref name = "Greenwood"/> MnO has the distinction of being one of the first compounds<ref>J.E Greedon, (1994), ''Magnetic oxides'' in Encyclopedia of Inorganic chemistry Ed. R. Bruce King, John Wiley & Sons {{ISBN|0-471-93620-0}}</ref> to have its magnetic structure determined by [[neutron diffraction]], the report appearing in 1951.<ref>{{cite journal | last1=Shull | first1=C. G. | last2=Strauser | first2=W. A. | last3=Wollan | first3=E. O. | title=Neutron Diffraction by Paramagnetic and Antiferromagnetic Substances | journal=Physical Review | publisher=American Physical Society (APS) | volume=83 | issue=2 | date=1951-07-15 | issn=0031-899X | doi=10.1103/physrev.83.333 | pages=333–345}}</ref> This study showed that the Mn²⁺ ions form a face centered cubic magnetic sub-lattice where there are ferromagnetically coupled sheets that are anti-parallel with adjacent sheets.

Manganese(II) oxide undergoes the [[chemical reaction]]s typical of an ionic oxide. Upon treatment with acids, it converts to the corresponding manganese(II) salt and [[water]].<ref name = "Greenwood"/> Oxidation of manganese(II) oxide gives [[manganese(III) oxide]].

MnO occurs in nature as the rare mineral [[manganosite]].<br /> It is prepared commercially by reduction of MnO₂ with [[hydrogen]], [[carbon monoxide]] or [[methane]], e.g.:<ref name=Reidies/>

:MnO₂ + H₂ → MnO + H₂O

Upon heating to 450{{nbsp}}°C, [[manganese(II) nitrate]] gives a mixture of oxides, MnO_2-x, which can be reduced to the monoxide with hydrogen at ≥750{{nbsp}}°C.<ref>{{cite book|author1=H. Lux|chapter=Manganeses(II) Oxide|title=Handbook of Preparative Inorganic Chemistry, 2nd Ed. |editor=G. Brauer|publisher=Academic Press|year=1963|place=NY, NY|volume=2pages=1455}}</ref>

MnO is particularly stable and resists further reduction.<ref name=UllMn>{{cite book |doi=10.1002/14356007.a16_077|chapter=Manganese and Manganese Alloys |title=Ullmann's Encyclopedia of Industrial Chemistry |year=2000 |last1=Wellbeloved |first1=David B. |last2=Craven |first2=Peter M. |last3=Waudby |first3=John W. |isbn=3527306730 }}</ref>

MnO can also be prepared by heating the carbonate:<ref>W.H. McCarroll (1994) ''Oxides- Solid State Chemistry'', Encyclopedia of Inorganic Chemistry Ed. R. Bruce King, John Wiley & Sons {{ISBN|0-471-93620-0}}</ref>

This [[calcining]] process is conducted anaerobically, lest [[Manganese(III) oxide|Mn₂O₃]] form.

An alternative route, mostly for demonstration purposes, is the oxalate method, which also applicable to the synthesis of [[ferrous oxide]] and [[stannous oxide]]. Upon heating in an oxygen-free atmosphere (usually CO₂), manganese(II) oxalate decomposes into MnO:<ref>Arthur Sutcliffe (1930) Practical Chemistry for Advanced Students (1949 Ed.), John Murray - London.</ref>

:[[Manganese oxalate|MnC₂O₄]]·2H₂O → MnO + CO₂ + CO + 2 H₂O

Together with manganese sulfate, MnO is a component of [[fertilizer]]s and food additives. Many thousands of tons are consumed annually for this purpose. Other uses include: a [[catalyst]] in the manufacture of [[allyl alcohol]], ceramics, paints, colored glass, bleaching tallow and textile printing.<ref name=Reidies/>

{{reflist|30em}}

{{oxides}}

[[Category:Manganese(II) compounds]]

[[Category:Transition metal oxides]]

[[Category:Rock salt crystal structure]]