Thorium diiodide

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.^[3]

Thorium diiodide

Identifiers
CAS Number	13779-95-8
3D model (JSmol)	Interactive image
PubChem CID	21115822
InChI InChI=1S/2HI.Th/h2*1H;/q;;+2/p-2 Key: WASWCTHKYRRDNN-UHFFFAOYSA-L
SMILES [Th+2].[I-].[I-]
Properties
Chemical formula	ThI2
Molar mass	612.75
Appearance	golden metallic
Density	7.21 g/cm3[1]
Melting point	850 °C[2]
Solubility in water	soluble
Structure
Crystal structure	hexagonal
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	Radioactive
Related compounds
Other cations	Cerium diiodide Praseodymium diiodide Gadolinium diiodide
Related compounds	Thorium triiodide Thorium tetraiodide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Preparation

Thorium diiodide cn be prepared by heating thorium tetraiodide in stoichiometric amounts of thorium:^[3][4]

ThI₄ + Th → 2 ThI₂

It can also be prepared by directly reacting thorium and iodine:^[4]

Th + I₂ → ThI₂

Thorium diiodide can also be prepared from the decomposition of thorium triiodide at temperatures above 550 °C:^[4]

2 ThI₃ → ThI₄ + ThI₂

Properties

Like the diiodides of cerium, praseodymium and gadolinium, it has a metallic gold lustre and high electrical conductivity.^[3]