A range of chloroindate(III) ionic liquid systems was prepared by mixing of 1-alkyl-3-methylimidazolium chloride with indium(III) chloride in various ratios, expressed as the mol fraction of indium(III) chloride, χInCl3. For χInCl3 ≤ 0.50, the products were liquids, whereas for χInCl3 > 0.50, the products were biphasic (suspensions of a solid in an ionic liquid). Speciation of these chloroindate(III) systems was carried out using a wide range of techniques: differential scanning calorimetry (DSC), polarised optical microscopy (POM), liquid-state and solid-state 115In NMR spectroscopy, X-ray photoelectron spectroscopy (XPS) and extended X-ray absorption fine structure (EXAFS). Ionic liquids prepared using an excess of the organic chloride (χInCl3 < 0.5) contained [InCl6]3−, [InCl5]2− and [InCl4]− anions, in proportions dependent on the χInCl3 value. Equimolar mixtures yielded single compounds: 1-alkyl-3-methylimidazolium tetrachloroindates(III). Systems containing an excess of indium(III) chloride (χInCl3 > 0.5) contained indium(III) chloride powder suspended in a neutral tetrachloroindate ionic liquid.
