A treatise on chemistry / by H.E. Roscoe and C. Schorlemmer.

  • Roscoe, Henry E. (Henry Enfield), 1833-1915
Date:
1883
Catalogue details

Licence: Public Domain Mark

Credit: A treatise on chemistry / by H.E. Roscoe and C. Schorlemmer. Source: Wellcome Collection.

    513/520 (page 501)
    the chloride, and the iodide is a yellow crystalline mass, which on heating melts to form a reddish-brown liquid. Indium Sulphite, In2(S03)3 + 4H.,0. This is a crystalline powder, the preparation of which has been already described. It dissolves easily in aqueous sulphurous acid, and separates out on evaporation in distinct crystals. Indium Sulphate, In2(S04)3, is obtained by the careful evaporation of a solution of the oxide in an excess of sulphuric acid, in the form of a white powder very soluble in water. On strongly heating it is converted into an insoluble basic salt. On evaporating the acid solution under the desiccator, deli- quescent crystals of the acid salt having the composition H2Tn2 (S04)4 + 8H20 are deposited. Indium-Ammonium Alum, In2(S04)3 + (NH4)2S04 + 24H20, is deposited in well-defined regular octohedrons, which dissolve at 16° in half their weight, and at 40° in about a quarter of their weight of water and melt at 36V If a solution be allowed to crystallize at this temperature crystals of the hydrate In2(S04)3 + (NH4)2S04 + SII20, separate out. Potassium and sodium form analogous hydrates. The corre- sponding alums (containing 24 molecules of water) have not been obtained with indium and the fixed alkalis. Indium Nitrate, In2(N03)6 + 3H20, forms deliquescent needles soluble in both water and absolute alcohol. These on heating are easily converted into a basic salt. Indium Sulphide, In2S3. Indium and sulphur combine together at a temperature near redness, with evolution of heat, to form a brown infusible mass. Sulphuretted hydrogen passed into a solution of an indium salt which is not too acid or too con- centrated, precipitates yellow indium sulphide, which on heating with sulphide of ammonium is converted into the white hydro- sulphide. Detection and Estimation of Indium. 309 The indium compounds are distinguished inasmuch as when moistened with hydrochloric acid they tinge the non- luminous gas-flame a dark-blue colour. The spectrum consists of an intense indigo-blue line, Ina w.l. 4509, and a less intense violet line, In/3 w.l. 4101. It is from the above reaction that the metal derives its name. 1 Rossler, Journ. Pract. CJiem. [2], vii. 14