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It may refer more specifically to the following manganese minerals: Birnessite, (Na,Ca) 0.5 (Mn IV,Mn III) 2 O 4 · 1.5 H 2 O; Buserite, MnO 2 ·nH 2 O; Hausmannite, Mn II Mn III 2 O 4; Manganite, Mn III O(OH)
Manganese(II,III) oxide is the chemical compound with formula Mn 3 O 4. Manganese is present in two oxidation states +2 and +3 and the formula is sometimes written as MnO·Mn 2 O 3. Mn 3 O 4 is found in nature as the mineral hausmannite.
MnCO 3 → MnO + CO 2. This calcining process is conducted anaerobically, lest Mn 2 O 3 form. An alternative route, most interest for demonstration purposes, is the "oxalate method". Also applicable to the synthesis of ferrous oxide and stannous oxide, it entails heating in an oxygen-free atmosphere (often CO 2), hydrated manganese(II) oxalate: [9]
Rhodochrosite is a manganese carbonate mineral with chemical composition MnCO 3. In its pure form (rare), it is typically a rose-red colour, [5] but it can also be shades of pink to pale brown. It streaks white, [6] and its Mohs hardness varies between 3.5 and 4.5. Its specific gravity is between 3.45 and 3.6. [7]
In Mn(CH 3) 2 (dmpe) 2, Mn(II) is low spin, which contrasts with the high spin character of its precursor, MnBr 2 (dmpe) 2 (dmpe = (CH 3) 2 PCH 2 CH 2 P(CH 3) 2). [38] Polyalkyl and polyaryl derivatives of manganese often exist in higher oxidation states, reflecting the electron-releasing properties of alkyl and aryl ligands. One example is [Mn ...
Heating MnO 2 in air at below 800 °C produces α-Mn 2 O 3 (higher temperatures produce Mn 3 O 4). [5] γ-Mn 2 O 3 can be produced by oxidation followed by dehydration of manganese(II) hydroxide. [5] Many preparations of nano-crystalline Mn 2 O 3 have been reported, for example syntheses involving oxidation of Mn II salts or reduction of MnO 2 ...
MMT has been used in Canadian gasoline since 1976 (and in numerous other countries for many years) at a concentration up to 8.3 mg Mn/L (though the importation and interprovincial trade of gasoline containing MMT was restricted briefly during the period 1997–1998) [3] [4] and was introduced into Australia in 2000. It has been sold under the ...
Many enzymatic systems need Mn to function, but in high levels, Mn can become toxic. One environmental reason Mn levels can increase in seawater is when hypoxic periods occur. [14] Since 1990 there have been reports of Mn accumulation in marine organisms including fish, crustaceans, mollusks, and echinoderms.