Rubidium triiodide

Rubidium triiodide is an inorganic compound with the chemical formula RbI3. It is composed of Rb+ and.

Preparation
Rubidium triiodide can be obtained by heating rubidium iodide and iodine in aqueous solution:


 * 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. Upon heating to 270 °C, the rubidium triiodide decomposes into rubidium iodide and elemental iodine. It is soluble in ethanol and decomposes in ether.

Reactions
It has long been believed that rubidium triiodide reacts further with iodine to form RbI7 and RbI9, but this has been refuted by recent studies.