Manganese (II) oxide

Crystal structure
__ Mn 2+      __ O 2−
General
Surname	Manganese (II) oxide
other names	Manganese oxide Manganese monoxide Manganese green Manganese Oxidul (obsolete) Manganese oxide (obsolete) Manganosite (mineral)
Ratio formula	MnO
Brief description	green powder
External identifiers / databases
CAS number 1344-43-0 EC number 215-695-8 ECHA InfoCard 100.014.269 PubChem 14940 Wikidata Q414669
properties
Molar mass	70.94 g mol −1
Physical state	firmly
density	5.45 g cm −3
Melting point	1650 ° C
solubility	almost insoluble in water soluble in acids and ammonium chloride
safety instructions
GHS labeling of hazardous substances no GHS pictograms H and P phrases H: no H-phrases P: no P-phrases
MAK	0.5 mg m −3
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Manganese (II) oxide is one of the oxides of manganese with the formula MnO.

Occurrence

Manganese oxide occurs naturally in the mineral manganosite .

Extraction and presentation

Manganese (II) oxide is by reduction of manganese (IV) oxide -containing ores with natural gas or coal at temperatures between 400 and 1000 ° C. Manganese (II) oxide formed must be cooled under protective gas in order to avoid reoxidation to tetravalent manganese.

${\displaystyle \mathrm {MnO_{2}+CO\longrightarrow MnO+CO_{2}} }$

${\displaystyle \mathrm {MnO_{2}+H_{2}\longrightarrow MnO+H_{2}O} }$

Manganese (II) oxide can also be obtained by heating manganese (II) carbonate MnCO ₃ in a vacuum:

${\displaystyle \mathrm {MnCO_{3}\longrightarrow MnO+CO_{2}} }$

properties

Manganese (II) oxide crystallizes in the cubic sodium chloride structure . MnO is an antiferromagnetic insulator at low temperatures , the magnetic structure of which was one of the first compounds to be elucidated. For this purpose, neutron diffraction experiments were carried out as early as 1951 , which showed that the magnetic moments of Mn ²⁺ each align against those of all of its neighbors. That is the meaning of antiferromagnetism: the magnetic moments are aligned with each other and thus cancel each other out, the material initially appears non-magnetic. However, this alignment also means that all magnetic moments are aligned parallel to one another along the spatial diagonal . At very low temperatures, this leads to a slight rhombohedral distortion precisely along this direction, which is denoted by [111] . Above the order temperature of 110 K, known as the Néel temperature , manganese (II) oxide becomes paramagnetic .

use

Manganese (II) oxide is used as a component of casting powder in the metalworking industry, as a fertilizer additive or feed additive, and as a green color pigment in fabric printing .

safety instructions

Powdered, freshly produced manganese (II) oxide can self-ignite in air.

Individual evidence

1. ↑ ^{a b c d e f g h} Entry for CAS no. 1344-43-0 in the GESTIS substance database of the IFA , accessed on May 9, 2017(JavaScript required) .
2. ^ National Pollutant Inventory: Manganese & compounds. accessed on February 17, 2015.
3. ↑ Manganosit (Mineral Atlas)
4. ↑ The discovery of manganosite in the Harz Mountains (Stollen Troll)
5. ↑ WH McCarroll: Oxides- solid state chemistry. In: R. Bruce King (Ed.): Encyclopedia of Inorganic chemistry. John Wiley & Sons, 1994, ISBN 0-471-93620-0 .
6. ↑ JE Greedon: Magnetic oxides. In: R. Bruce King (Ed.): Encyclopedia of Inorganic chemistry. John Wiley & Sons, 1994, ISBN 0-471-93620-0 .
7. ↑ CG Shull, WA Strauser, EO Wollan: Neutron Diffraction by Paramagnetic and Anti Ferromagnetic Substances. In: Phys. Rev. Volume 83, 1951, pp. 333-345. doi: 10.1103 / PhysRev.83.333
8. ↑ G. Gigacher, Ch. Bernhard, W. Kriegner: Properties of high-manganese steels under conditions similar to continuous casting. ( Memento from September 29, 2007 in the Internet Archive )
9. ↑ Manganese and its compounds (University of Regensburg)