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.
Thorium diiodide cn be prepared by heating thorium tetraiodide in stoichiometric amounts of thorium:
It can also be prepared by directly reacting thorium and iodine:[1]
Thorium diiodide can also be prepared from the decomposition of thorium triiodide at temperatures above 550 °C:
Like the diiodides of cerium, praseodymium and gadolinium, it has a metallic gold lustre and high electrical conductivity.