Manganite


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manganite

[′maŋ·gə‚nīt]
(mineralogy)
MnO(OH) A brilliant steel-gray or black polymorphous mineral; crystallizes in the orthorhombic system. Also known as gray manganese ore.

Manganite

 

a mineral of the oxide and hydroxide class. It has a chemical composition of MnO(OH) and contains 80.66 percent MnO; admixtures of Fe, Al, Ba, Pb, Cu, and other elements are sometimes present. Manganite crystallizes in the monoclinic system, forming prismatic steel-gray pseudoorthorhombic crystals with a submetallic luster and perfect cleavage. It generally occurs as black or brown (hydromanganite) finely crystalline masses. Concretions and oolitic formations are also widespread. Manganite is brittle. It has a hardness of 3-4 on Mohs’ scale and a density of 4,200-4,330 kg/m3.

Manganite, along with other manganese oxides (pyrolusite, psilomelane), enters into the composition of large sedimentary manganese ore deposits that are formed in the littoral zones of marine basins under conditions of some oxygen deficiency. Manganite also occurs in hydrothermal vein deposits in association with calcite, quartz, barite, and, sometimes, rhodochrosite. It is converted into sooty cryptocrystalline pyrolusite during surface oxidation. Manganite serves as an important source material in the manufacture of ferromanganese and other manganese alloys required for the smelting of special steels.

REFERENCE

Mineraly; spravochnik, vol. 2, fasc. 3. Moscow, 1967.
References in periodicals archive ?
Puri, "Raman studies of Rod-like Bismuth strontium manganites," European Journal of Applied Engineering & Scientific Research, vol.
In this region of workings, generally called the Braunsteinzeche ("braunstein mining area"), manganite was the chief ore species.
2), a large tabular body of fault breccia is composed of felsic rock cemented by manganese oxides and containing massive botryoidal psilomelane and braunite, as well as crystals and needles of manganite in rugs with barite.
Summary: TEHRAN (FNA)- Iranian researchers from Tabriz and Mazandaran universities made a breakthrough in eliminating volatile organic compounds that pollute the air by producing manganite nanocatalysts with spinel structure.
They consider such topics as the non-equilibrium magnetism of single-domain particles for characterizing magnetic nanomaterials, site disorder and finite size effects in rare-earth manganites, processing and the properties of thin manganite films, studying magnetic properties of semiconductors and nanomaterials by different theoretical methods, obtaining magnetic and electric information on organic systems using electron spin resonance, and the orbital dilution effect in the Mott insulating system.
Investigations of magnetoresistance of manganite thin films in pulsed magnetic fields were some of them [4].
Not represented at this show, but lovingly described to me by Paul, were specimens from the same pocket zone which show excellent crystal development of olmiite, ettringite, manganite and a few other species.
3] (LCMO) manganite is en ideal system to study exchange bias effect, because depending of the Ca content the system exhibit ferro and antiferromagnetic behavior.
This 50% doped manganite perovskite is a single phase at 300 K but separates into three different, magnetically ordered phases at low temperatures.
As part of a tubular cell, the solid electrolyte is surrounded by a lanthanum manganite air electrode and a fuel electrode made from nickel embedded in yttria-stabilized zirconia.
The process uses low cost chemical precursors to nucleate and directly deposit nanoparticles of materials such as yttria-stabilized zirconia, doped lanthanum manganite or doped lanthanum chromite to form cell, interconnect and sealing layers.