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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.
Two forms are generally recognized, α-Mn 2 O 3 and γ-Mn 2 O 3, [10] although a high pressure form with the CaIrO 3 structure has been reported too. [ 11 ] α-Mn 2 O 3 has the cubic bixbyite structure, which is an example of a C-type rare earth sesquioxide ( Pearson symbol cI80, space group Ia 3 , #206).
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)
The most stable are 53 Mn with a half-life of 3.7 million years, 54 Mn with a half-life of 312.2 days, and 52 Mn with a half-life of 5.591 days. All of the remaining radioactive isotopes have half-lives of less than three hours, and the majority of less than one minute.
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]
Other enzymes containing manganese are arginase and Mn-containing superoxide dismutase ... 1–3 1.2 1–3 1.2 4–8 1.5 4–8 1.5 9–13 1.9 9–13 1.6 14–18 2.2
Manganese triacetate has been used as a one-electron oxidant.It can oxidize alkenes via addition of acetic acid to form lactones. [3]This process is thought to proceed via the formation of a •CH 2 CO 2 H radical intermediate, which then reacts with the alkene, followed by additional oxidation steps and finally ring closure. [1]
Naturally occurring manganese (25 Mn) is composed of one stable isotope, 55 Mn. Twenty-seven radioisotopes have been characterized, with the most stable being 53 Mn with a half-life of 3.7 million years, 54 Mn with a half-life of 312.3 days, and 52 Mn with a half-life of 5.591 days.