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|Section2= |Section4= |Section7= |Section8= }} Manganese(IV) oxide is the inorganic compound with the formula . This 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 MnO2 is for dry-cell batteries, such as the alkaline battery and the zinc-carbon battery.〔.〕 is also used as a pigment and as a precursor to other manganese compounds, such as . It is used as a reagent in organic synthesis, for example, for the oxidation of allylic alcohols. MnO2 in the α polymorph can incorporate a variety of atoms (as well as water molecules) in the "tunnels" or "channels" between the magnesium oxide octahedra. There is considerable interest in α-MnO2 as a possible cathode for lithium ion batteries. ==Structure== Several polymorphs of are claimed, as well as a hydrated form. Like many other dioxides, crystallizes in the rutile crystal structure (this polymorph is called β-), with three-coordinate oxide and octahedral metal centres.〔 is characteristically nonstoichiometric, being deficient in oxygen. The complicated solid-state chemistry of this material is relevant to the lore of "freshly prepared" in organic synthesis. The α-polymorph of has a very open structure with ``channels" which can accommodate metal atoms such as silver or barium. α-MnO2 is often called Hollandite, after a closely related mineral. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Manganese dioxide」の詳細全文を読む スポンサード リンク
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