Thulium(III) iodide is an iodide of thulium, with the chemical formula of TmI3. Thulium(III) iodide is used as a component of metal halide lamps.
Preparation
Mercury(II) iodide can be heated with thulium to obtain thulium(III) iodide:Georg Brauer (Hrsg.), unter Mitarbeit von Marianne Baudler u. a.: Handbuch der Präparativen Anorganischen Chemie. 3., umgearbeitete Auflage. Band I, Ferdinand Enke, Stuttgart 1975, ISBN 3-432-02328-6, S. 1077.
2 Tm + 3 HgI2 → 2 TmI3 + 3 Hg
The mercury produced in the reaction can be removed by distillation.Asprey, L. B.; Keenan, T. K.; Kruse, F. H. Preparation and crystal data for lanthanide and actinide triiodides. Inorg. Chem., 1964. 3 (8): 1137-1240
The thulium(III) iodide hydrate crystallized from solution can be heated with ammonium iodide to obtain the anhydrous form.无机化学丛书 第七卷 钪 稀土元素. 科学出版社. pp 211
Properties
Thulium(III) iodide is a yellow, highly hygroscopic solid with a bismuth(III) iodide-type crystal structure. It forms in the hexagonal crystal system. Its hydrate can be heated in air to obtain TmOI. Its anhydrous form can be heated with thulium to obtain TmI2:（注：此文献指出Tm+HgI2的反应生成TmI2）
2 TmI3 + Tm → 3 TmI2
References