Rubidium triiodide is an inorganic compound with the chemical formula RbI3. It is composed of Rb+ and I− 3.
Preparation
Rubidium triiodide can be obtained by heating rubidium iodide and iodine in aqueous solution:[1]
RbI + I2 → RbI3
Properties
Rubidium triiodide is an orthorhombic black crystal, isomorphic to caesium triiodide, with space group Pnma, unit cell parameters a = 1090.8 pm, b = 665.5 pm, c = 971.1 pm.[2] Upon heating to 270 °C, the rubidium triiodide decomposes into rubidium iodide and elemental iodine.[1] It is soluble in ethanol and decomposes in ether.[1]
Reactions
It has long been believed that rubidium triiodide reacts further with iodine to form RbI7 and RbI9,[3] but this has been refuted by recent studies.[4][2]
^ abTebbe, K. F.; Georgy, U. (1986-12-15). "Die Kristallstruckturen von Rubidiumtriiodid und Thalliumtriiodid". Acta Crystallographica Section C Crystal Structure Communications. 42 (12). International Union of Crystallography (IUCr): 1675–1678. doi:10.1107/s0108270186090972. ISSN0108-2701.
^Briggs, T. R.; Patterson, E. S. (1932-10-01). "The Polyiodides of Rubidium. I". The Journal of Physical Chemistry. 36 (10). American Chemical Society (ACS): 2621–2624. doi:10.1021/j150340a011. ISSN0092-7325.