Rhenium(III) iodide

Rhenium(III) iodide is a binary chemical compound of rhenium and iodide with the chemical formula.

Synthesis
Rhenium(III) iodide can be synthesized by the decomposition of rhenium(IV) iodide:
 * 2ReI4 -> 2ReI3 + I2

Another way to make it is by introduction of ethanol into a mixture of perrhenic acid and hydroiodic acid.


 * HReO4 + 3HI + 2C2H5OH -> ReI3 + 4H2O + 2CH3CHO

Physical properties
Rhenium(III) iodide forms violet-black crystals. It is poorly soluble in water, acetone, ethanol, ether, and dilute acid solutions.

Chemical properties
When heated in vacuum up to 170 °C, the compound decomposes to rhenium(II) iodide, and at 380 °C — to rhenium(I) iodide:
 * 2ReI3 -> 2ReI2 + I2
 * ReI3 -> ReI + I2