Rubidium triiodide

Rubidium triiodide is an inorganic compound with the chemical formula RbI₃. It is composed of Rb⁺ and I⁻
₃.

Rubidium triiodide

Identifiers
CAS Number	12298-69-0 Y
3D model (JSmol)	Interactive image
PubChem CID	23717888
InChI InChI=1S/I3.Rb/c1-3-2;/q-1;+1 Key: PXHPKMRCAYWMAT-UHFFFAOYSA-N
SMILES [Rb+].I[I-]I
Properties
Chemical formula	RbI3
Appearance	black crystals
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

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]