Thorium diiodide is an iodide of thorium, with the chemical formula of ThI2. It is an electride with the ionic formula Th4+(I−)2e−2. It is air-sensitive.

Preparation

Thorium diiodide cn be prepared by heating thorium tetraiodide in stoichiometric amounts of thorium:

ThI4 + Th → 2 ThI2

It can also be prepared by directly reacting thorium and iodine:

Th + I2 → ThI2

Thorium diiodide can also be prepared from the decomposition of thorium triiodide at temperatures above 550°C:

2 ThI3 → ThI4 + ThI2

Properties

Like the diiodides of cerium, praseodymium and gadolinium, it has a metallic gold lustre and high electrical conductivity.