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Manganese is also important in photosynthetic oxygen evolution in chloroplasts in plants. The oxygen-evolving complex (OEC) is a part of photosystem II contained in the thylakoid membranes of chloroplasts; it is responsible for the terminal photooxidation of water during the light reactions of photosynthesis , and has a metalloenzyme core ...
Polymetallic nodules, also called manganese nodules, are mineral concretions on the sea bottom formed of concentric layers of iron and manganese hydroxides around a core. As nodules can be found in vast quantities, and contain valuable metals, deposits have been identified as a potential economic interest. [ 1 ]
Manganese precipitates in soils in the form of manganese-iron oxide minerals, which promote nutrient and organic matter accumulation due to their high surface area. Manganese is the tenth most abundant metal in the Earth's crust, making up approximately 0.1% of the total composition, or about 0.019 mol kg −1 , which is found mostly in the ...
Manganese has no satisfactory substitute in these applications in metallurgy. [53] Steelmaking, [74] including its ironmaking component, has accounted for most manganese demand, presently in the range of 85% to 90% of the total demand. [61] Manganese is a key component of low-cost stainless steel.
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.
Manganese(IV) oxide is a blackish or brown solid occurs naturally as the mineral pyrolusite, which is the main ore of manganese and a component of manganese nodules. The principal use for MnO 2 is for dry-cell batteries, such as the alkaline battery and the zinc–carbon battery. [6] Manganese(VII) oxide is dark green in its crystalline form.
Manganese may also form mixed oxides with other metals : Bixbyite, (Fe III,Mn III) 2 O 3, a manganese(III) iron(III) oxide mineral; Jacobsite, Mn II Fe III 2 O 4, a manganese(II) iron(III) oxide mineral; Columbite, (Fe II,Mn II)Nb 2 O 6, a niobate of iron(II) and manganese(II) Tantalite, (Fe II,Mn II)Ta 2 O 6, a tantalum(V) mineral group close ...
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 .