Search results
Results from the WOW.Com Content Network
Manganese is an essential human dietary element and is present as a coenzyme in several biological processes, which include macronutrient metabolism, bone formation, and free radical defense systems. Manganese is a critical component in dozens of proteins and enzymes. [8] The human body contains about 12 mg of manganese, mostly in the bones.
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) Manganosite, Mn II O; Psilomelane, Ba(Mn II)(Mn IV) 8 O 16 (OH) 4, or (Ba,H 2 O) 2 Mn 5 O 10; Pyrolusite, Mn IV O 2; Manganese may also ...
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]
The color of chemicals is a physical property of chemicals that in most cases comes from the excitation of electrons due to an absorption of energy performed by the chemical. The study of chemical structure by means of energy absorption and release is generally referred to as spectroscopy .
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 also substitutes for (Fe,Mg) within cummingtonite amphibole, replacing B site atoms. These minerals are found in high-grade metamorphic banded iron formation and form a compositional series between Mn 2 Mg 5 Si 8 O 22 (OH) 2 (tirodite) and Mn 2 Fe 5 Si 8 O 22 (OH) 2 (dannemorite). Calcium, sodium and potassium concentrations in ...
Manganese(II) oxide is an inorganic compound that forms green crystals. Like many monoxides, MnO adopts the rock salt structure, where cations and anions are both octahedrally coordinated. Also like many oxides, manganese(II) oxide is often nonstoichiometric: its composition can vary from MnO to MnO 1.045. [6]
Hausmannite is a complex oxide, or a mixed oxide, of manganese containing both di-and tri-valent manganese. Its chemical formula can be represented as Mn II Mn III 2 O 4, or more simply noted as MnO·Mn 2 O 3, or Mn 3 O 4, as commonly done for magnetite (Fe 3 O 4), the corresponding iron oxide. It belongs to the spinel group and forms ...