Manganese III oxide

The Mn ion is so unstable that it scarcely exists in aqueous solution. In acidic aqueous solution, manganic compounds readily disproportionate to form Mn ions and hydrated manganese(IV) oxide, Mn02 2H20 in basic solution these compounds hydroly2e to hydrous manganese(III) oxide, MnO(OH). Sulfuric acid concentrations of about 400 450 g/L are required to stabilize the noncomplexed Mn ion in aqueous solutions. 

Manganese(III) Oxides. The sesquioxide, Mn202, exists in dimorphic forms. The a-Mri202 exists in nature as the mineral bixbyite. 

Manganoxyd, n. manganese oxide, specif, manganic oxide, manganese (III) oxide. — rotes mangano-manganic oxide, manganese-(II,III) oxide. 

A detailed study of the dehydrogenation of 10.1 l-dihydro-5//-benz[6,/]azcpinc (47) over metal oxides at 550 C revealed that cobalt(II) oxide, iron(III) oxide and manganese(III) oxide are effective catalysts (yields 30-40%), but formation of 5//-dibenz[7),/]azepinc (48) is accompanied by ring contraction of the dihydro compound to 9-methylacridine and acridine in 3-20 % yield.111 In contrast, tin(IV) oxide, zinc(II) oxide. chromium(III) oxide, cerium(IV) oxide and magnesium oxide arc less-effective catalysts (7-14% yield) but provide pure 5H-dibenz[b,/]azepine. On the basis of these results, optimum conditions (83 88% selectivity 94-98 % yield) for the formation of the dibenzazepine are proposed which employ a K2CO,/ Mn203/Sn02/Mg0 catalyst (1 7 3 10) at 550 C. 

Manganese (III) oxide reacts violently with hydrogen peroxide. 

The hydroxide is rapidly oxidized in air forming manganese(III) oxide, Mn20s. 

Manganese(III) oxide occurs in nature as the mineral braunite. The oxide is used in the production of ferrites and thermistors. 

A highly active gamma-Mn02 can be produced by treating manganese(III) oxide with hot sulfuric acid ... 

Najafpour MM, Ehrenberg T, Wiechen M, Kurz P. Calcium manganese(III) oxides (CaMn204 x H20) as biomimetic oxygen-evolving catalysts. Angew Chem Int Ed. 2010 49(12) 2233-7. 

One of the earliest examples of the synthetic promise of radical reactions for preparing polycyclic products was provided by Corey s y-lactone synthesis. This approach was actually based on a well-known reaction of a-carbonyl radicals, generated by manganese(iii) oxidation of carboxylic acids, with unsaturated substrates. The mechanism of the basic steps shown for the preparation of lactone 418 (Scheme 2.140) involves initial addition of the a-carbonyl radical 419 to the double bond of styrene, followed by oxidation of the radical intermediate 419a to carbocation 419b, and subsequent intramolecular reaction with the carboxyl nucleophile to yield the lactone product. 

Lithium batteries can be either primary or secondary, depending on which reduchon reachons are coupled to the oxidahon of hthium. For example, some hthium batteries use the same cathode reaction as zinc-carbon dry cells, the reduchon of manganese(IV) oxide (Mn02) to manganese(III) oxide (Mn203). These baheries produce electric current at about 3 V compared to 1.5 V for zinc-carbon cells. Lithium batteries last much longer than other kinds of batteries. As a result, they are often used in watches, computers, and cameras to maintain hme, date, memory, and personal sethngs—even when the device is turned off. 

Manganese(II,III) Oxide (Mn304) and Manganese(III) Oxide (Mn203)... 

Manganese(III) oxide is formed when manganese IV) oxide is heated at 600 to 800 C ... 

Mn203 Mn203, dimanganese trioxide, manganese(III) oxide ... 

Objective 15 57. Manganese metal is produced from the manganese(III) oxide, Mn203, which... 

Manganese(III) oxide, Mn203(s). exists in equilibrium with Mn(OH)2(s) (line D) if conditions are sufficiently basic or with Mn2+(aq) (line E) at somewhat lower pH values ... 

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