Manganese(II) oxide is an

inorganic compound An inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds⁠that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as ''inorganic chemistry''. Inorgan ...

with

chemical formula A chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, such as pare ...

MnO.Arno H. Reidies "Manganese Compounds" Ullmann's Encyclopedia of Chemical Technology 2007; Wiley-VCH, Weinheim. It forms green crystals. The compound is produced on a large scale as a component of

fertilizer A fertilizer or fertiliser is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from liming materials or other non-nutrient soil amendments. Man ...

s and

food additives Food additives are substances added to food to preserve flavor or enhance taste, appearance, or other sensory qualities. Some additives, such as vinegar ( pickling), salt ( salting), smoke (smoking) and sugar (crystallization), have been used for ...

Structure, stoichiometry, reactivity

Like many metal monoxides, MnO adopts the rock salt structure, where cations and anions are both octahedrally coordinated. Also like many metal oxides, manganese(II) oxide is often nonstoichiometric: its composition can vary from MnO to MnO_1.045. Below 118 K, MnO is

antiferromagnetic In materials that exhibit antiferromagnetism, the magnetic moments of atoms or molecules, usually related to the spins of electrons, align in a regular pattern with neighboring Spin (physics), spins (on different sublattices) pointing in oppos ...

. MnO has the distinction of being one of the first compounds to have its magnetic structure determined by

neutron diffraction Neutron diffraction or elastic neutron scattering is the application of neutron scattering to the determination of the atomic and/or magnetic structure of a material. A sample to be examined is placed in a beam of Neutron temperature, thermal or ...

, the report appearing in 1951. 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 A chemical reaction is a process that leads to the chemistry, chemical transformation of one set of chemical substances to another. When chemical reactions occur, the atoms are rearranged and the reaction is accompanied by an Gibbs free energy, ...

s typical of an ionic oxide. Upon treatment with acids, it converts to the corresponding manganese(II) salt. Oxidation of manganese(II) oxide gives

manganese(III) oxide Manganese(III) oxide is a chemical compound with the formula Mn2O3. It occurs in nature as the mineral bixbyite (recently changed to bixbyite-(Mn)IMA 21-H: Redefinition of bixbyite and definition of bixbyite-(Fe) and bixbyite-(Mn). CNMNC Newslett ...

Preparation and occurrence

MnO occurs in nature as the rare mineral

manganosite Manganosite is a rare mineral composed of manganese(II) oxide MnO. It was first described in 1817 for an occurrence in the Harz Mountains, Saxony-Anhalt, Germany. It has also been reported from Langban and Nordmark, Sweden and at Franklin Furn ...

.
It is prepared commercially by reduction of MnO₂ with

hydrogen Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter ...

carbon monoxide Carbon monoxide (chemical formula CO) is a poisonous, flammable gas that is colorless, odorless, tasteless, and slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the si ...

methane Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The abundance of methane on Earth makes ...

, e.g.: :MnO₂ + H₂ → MnO + H₂O :MnO₂ + CO → MnO + CO₂ Upon heating to 450°C,

manganese(II) nitrate Manganese(II) nitrate refers to the inorganic compounds with formula Mn( NO3)2·(H2O)n. These compounds are nitrate salts containing varying amounts of water. A common derivative is the tetrahydrate, Mn(NO3)2·4H2O, but mono- and hexahydrates are ...

gives a mixture of oxides, denoted MnO_2−x, which can be reduced to the monoxide with hydrogen at ≥750°C. MnO is particularly stable and resists further reduction. MnO can also be prepared by heating the carbonate: :MnCO₃ → MnO + CO₂ This

calcining Calcination is thermal treatment of a solid chemical compound (e.g. mixed carbonate ores) whereby the compound is raised to high temperature without melting under restricted supply of ambient oxygen (i.e. gaseous O2 fraction of air), generally fo ...

process is conducted anaerobically, lest Mn₂O₃ form. An alternative route, most interest for demonstration purposes, is the "oxalate method". Also applicable to the synthesis of

ferrous oxide Iron(II) oxide or ferrous oxide is the inorganic compound with the formula FeO. Its mineral form is known as wüstite. One of several iron oxides, it is a black-colored powder that is sometimes confused with rust, the latter of which consists of ...

and

stannous oxide Tin(II) oxide (stannous oxide) is a compound with the formula SnO. It is composed of tin and oxygen where tin has the oxidation state of +2. There are two forms, a stable blue-black form and a metastable red form. Preparation and reactions Blu ...

, it entails heating in an oxygen-free atmosphere (often CO₂), hydrated manganese(II) oxalate:Arthur Sutcliffe (1930) Practical Chemistry for Advanced Students (1949 Ed.), John Murray - London. :MnC₂O₄·2H₂O → MnO + CO₂ + CO + 2 H₂O

Applications

Together with manganese sulfate, MnO is a component of

s and food additives. Many thousands of tons are consumed annually for this purpose. Other uses include: a

catalyst Catalysis () is the increase in rate of a chemical reaction due to an added substance known as a catalyst (). Catalysts are not consumed by the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quick ...

in the manufacture of allyl alcohol, ceramics, paints, colored glass, bleaching tallow and textile printing.

References

{{oxides Manganese(II) compounds Transition metal oxides Rock salt crystal structure