Atomistry » Indium » Chemical Properties » Indium sulphate
Atomistry »
  Indium »
    Chemical Properties »
      Indium sulphate »

Indium sulphate, In2(SO4)3

Indium sulphate, In2(SO4)3, may be prepared by dissolving indium, indium sesqui-oxide, or indium hydroxide in sulphuric acid, and carefully heating to expel water and excess of sulphuric acid. It is a white solid, very hygroscopic and extremely soluble in water, from which it is exceedingly difficult to crystallise out a hydrated sulphate. An ennea-hydrate, In2(SO4)3.9H2O, is said to exist, and an acid salt of the composition In2(SO4)3.H2SO4.8H2O is described as separating from an acid solution of the sulphate when evaporated over concentrated sulphuric acid.

The anhydrous sulphate has a density of 3.44 and a specific heat (between 0° and 100°) of 0.129.

Various double sulphates have been prepared by mixing indium sulphate solutions with solutions of other sulphates. The ammonium-, rubidium-, and caesium-indium alums, M2SO4.In2(SO4)3.24H2O (M = NH4, Rb, or Cs), can be thus prepared, the first having been discovered by Roessler and the others by Soret. Lithium, sodium, and potassium alums are not known, but sodium indium sulphate, Na2SO4.In2(SO4)3.8H2O, and the corresponding potassium, ammonium, and thallium salts have been prepared.

The three alums separate out in regular octahedra or combinations of the octahedron and cube. Their aqueous solutions have an acid reaction, and when heated become turbid owing to the separation of basic sulphates or, in the case of the caesium salt, indium hydroxide. The melting-points and solubilities of the alums in water (in grams of crystalline salt per 100 grams of water) are as follows : -

Solubilities
Temperature, °C.15°16.5°25°30°
Ammonium indium alumm.p. 36°...c. 200...c. 400
Rubidium indium alumm.p. 42°44.28.........
Caesium indium alumm.p. ?...3.04c. 11.7...


In the case of the ammonium alum, the "melting-point" is known to denote the transition-point, above which the alum breaks up into the octahydrate and water (Roessler): -

(NH4)2SO4.In2(SO4)3.24H2O ⇔ (NH4)2SO4.In2(SO4)3.8H2O + 16H2O.

The densities and refractive indices of the alums for the D-line at the ordinary temperature are given by Soret as follows: -

NH4RbCs
density2.0112.0652.241
μ1.46641.46381.4652

Last articles

Zn in 7OQY
Zn in 7PEL
Zn in 7OYG
Zn in 7P3S
Zn in 7PE7
Zn in 7RZC
Zn in 7PE9
Zn in 7PE8
Zn in 7RAG
Zn in 7RN5
© Copyright 2008-2020 by atomistry.com
Home   |    Site Map   |    Copyright   |    Contact us   |    Privacy