Mangan -hydroxid

Manganoxydul-hydrat, n. manganous hydroxide, manganese (II) hydroxide, -oxyd, n. mangano-manganic oxide, manganese (II,III)... 

The metal reacts slowly with water in cold, forming manganous hydroxide with the evolution of hydrogen ... 

Tetrammino-manganous Sulphate, [Mn(XH3).,]S04, is described by Rose 3 as the compound which is formed by allowing anhydrous sulphate to absorb ammonia. The salt falls to a white powder, and if kept for some time in a closed tube it turns brownish white, and in air loses ammonia. Solution in water causes the precipitation of manganous hydroxide. 

For the action of sulphur dioxide on manganic hydroxide, sec Meyer and Schramm, Zeitsch, anorg. Chem., 1923, 132, 226. 

A variation of the above tests is that devised by Lenher.1Ms which depends on tho low solubility of certain metal ions in alkaline solution. Treatment of an epoxide with concentrator aqueous man ganoua chloride, for example, causes the gradual appearance of a manganous hydroxide precipitate as OH ions are liberated (Eq. SS i). Other halides examined by Lenher but found to he less effective wore nine chloride, ferrous chloride, and stannous chloride. 

P. Wenger and C. Urfer. N. Smith found that in the oxidation of tin or copper in air, ammonia is simultaneously oxidized—induced reactions zinc has no action, but in glass dishes positive results were sometimes obtained—while only a slight action -was observed in the oxidation of ferrous and manganous hydroxides. 

It is based on the addition of Mn2+ solution, followed by die addition of a strong alkali to die sample in a glass-stoppered bottle. Dissolved 02 rapidly oxidizes an equivalent amount of the dispersed divalent manganous hydroxide precipitate to hydroxides of higher valence states. In die presence of iodide ions in an acidic solution, the oxidized manganese reverts to die divalent state, with die liberation of a quantity of iodine equivalent to die original dissolved 02 content. The iodine is then titrated with a standard solution of thiosulfate. The titration end point can be detected visually with a starch indicator, or by potentiometric techniques. The liberated iodine can be determined colorimetrically. 

Manganous hydroxide, Mn(OH)2, a light buff-colored precipitate. Insoluble in excess of NaOH. Oxidizes easily, turning dark brown or black as it comes in contact with air, Mn(OH)3. 

Derivation By the action of oxygen on precipitated manganous hydroxide. 

Derivation Action of hydrobromic acid with manganous carbonate or manganous hydroxide. 

Derivation Action of hydrogen fluoride on manganous hydroxide. 

Derivation Action of hydriodic acid on manganous hydroxide. 

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