Thorium(IV) iodide

Thorium(IV) iodide is an inorganic chemical compound composed of thorium and iodine with the chemical formula ThI₄. It is one of three known thorium iodides, the others being ThI₃ and ThI₂.

Thorium(IV) iodide

Names
Other names Thorium tetraiodide
Identifiers
CAS Number	7790-49-0 Y
3D model (JSmol)	Interactive image
ChemSpider	74233
ECHA InfoCard	100.029.283
EC Number	232-211-0
PubChem CID	82256
UNII	Y6WNI235O3 Y
CompTox Dashboard (EPA)	DTXSID90999095
InChI InChI=1S/4HI.Th/h4*1H;/q;;;;+4/p-4
SMILES [I-].[I-].[I-].[I-].[Th+4]
Properties[1]
Chemical formula	ThI4
Molar mass	739.656 g/mol
Appearance	white-yellow crystals
Density	6 g/cm3, solid
Melting point	570 °C (1,058 °F; 843 K)
Boiling point	837 °C (1,539 °F; 1,110 K)
Structure
Crystal structure	monoclinic
Coordination geometry	8 coordinate square antiprismatic
Thermochemistry
Std enthalpy of formation (ΔfH⦵298)	83 J/g
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Synthesis

Thorium(IV) iodide can be made by reacting thorium(IV) carbide or elemental thorium with iodine at 500 °C.^[2]

Th + 2 I₂ + → ThI₄

It can also be made from the reaction of Thorium(IV) hydride with hydrogen iodide.^[3]

Properties

Thorium(IV) iodide is an extremely air and moisture sensitive solid which exists in the form of crystal platelets that are orange when heated and yellow in the cold. It has a monoclinic crystal structure with the space group P2₁/n (space group no. 14, position 2) and the lattice parameters a = 1321.6 pm, b = 806.8 pm, c = 776.6 pm, β = 98.68°.^[2] It can also form a decahydrate. It forms complexes with Lewis bases. It reacts with thorium to form thorium(III) iodide and thorium(II) iodide.^[4]

Usage

Thorium(IV) iodide is used as an intermediate for the production of high-purity thorium by thermal decomposition of the compound (see Van Arkel-de Boer process)^[3]