A treatise on chemistry. Vol. II, Metals. Part II / by H.E. Roscoe & C. Schorlemmer ...

  • Henry Enfield Roscoe
Date:
1880
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Licence: Public Domain Mark

Credit: A treatise on chemistry. Vol. II, Metals. Part II / by H.E. Roscoe & C. Schorlemmer ... Source: Wellcome Collection.

Provider: This material has been provided by University of Bristol Library. The original may be consulted at University of Bristol Library.

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    Manganous sulphate is insoluble in absolute alcohol, this liquid removing a iDovtion of the water from the hydrates. Finely crystalline double sulphates are formed when manganous sulphate and the sulphates of the alkali-metals are crystallised together, and these are isomorphous with the corresponding salts formed by magnesium and by copper. Manganous Aluviinmm Sulphate, MnSO^-|-Al2(SO^)3 + 24H2O. This substance occurs as the mineral apjohnite found in Algoa Bay in South Africa.^ Manganous DitMonate, MnS20g + 3H2O. This salt is of interest inasmuch as it is employed for the preparation of dithionic acid (Vol. I. page 350). It is obtained by passing sulphur dioxide through water in which finely-divided manganese dioxide is suspended. The solution alwaj'^s contains a small quantity of manganese sulphate, and for this reason baryta water is added as long as a precipitate is formed. Manganese dithionate is deposited in easily soluble rliombohedral crystals. Manganous Nitrate, M.n(l:^0^)2 + 6H2O, crystallises with diffi- culty in white deliquescent needles which readily dissolve in alcohol. The salt melts on heating, and the liquid boils at 129°-5, at which temperature a black deposit of manganese oxide is formed. 318 Manganous Phosphates. These salts have been investi- gated by Heintz,^ Debray,^ Bodecker,* and Erlenmeyer.^ The normal manganous orthophosphate, MngfPOJa + 7H2O, is a white imperfectly crystalline precipitate. The monohydrogen salt. HMnP04 +SH^O, forms small prismatic rose-coloured rhombic crystals slightly soluble in water, and the dihydrogen phosphate, H4Mn(P0 + 2H2O, crystallises in red four-sided prisms which deliquesce on exposure to the air, decomposing ■ into free phos- phoric acid and the preceding salt. Man{ianous Arsenate. When arsenic acid is saturated with manganese carbonate, a difficultly soluble salt having the com- position HMnAsO^ is formed. This dissolves readily in arsenic acid with formation of the salt H4Mn(AsOj2. which latter crystallises in rectangular plates. Manganous Silicates frequently occur as isomorphous con- stituents of many minerals. Some naturally occurring man- ganese silicates are known. Thus, for instance, rhodonite, MnSiOg, ^ rhil. Mag. xii. 103. = Poqct. Jnn. Ixxiv. ino. 2 Arm. Cliem. Pharm. Ixix. 208. Ar<n. Chim. Phys. [.3], Ixi. 433. * Liebig's Ann. cxc. 101.
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