Zirconium(IV) iodide is the

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

with the formula Zr I₄. It is the most readily available iodide of zirconium. It is an orange-coloured solid that degrades in the presence of water. The compound was once prominent as an intermediate in the purification of zirconium metal.

Structure

Like most binary metal halides, zirconium(IV) iodide adopts a polymeric structure. As characterized by

X-ray crystallography X-ray crystallography is the experimental science of determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to Diffraction, diffract in specific directions. By measuring th ...

, the compound consists of octahedral Zr(IV) centers interconnected by four doubly bridging iodide ligands. The Zr-I distances of 2.692 (terminal) and 3.030 Å

Synthesis and reactions

This compound can be prepared by heating zirconium metal and an excess of iodine. . The solid is purified by sublimation (400 °C, 10-4 mm Hg). :

Pyrolysis Pyrolysis is a process involving the Bond cleavage, separation of covalent bonds in organic matter by thermal decomposition within an Chemically inert, inert environment without oxygen. Etymology The word ''pyrolysis'' is coined from the Gree ...

of zirconium(IV) iodide gas by contact with a hot wire was the first industrial process for the commercial production of pure ductile metallic zirconium. This

crystal bar process A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macrosc ...

was developed by Anton Eduard van Arkel and

Jan Hendrik de Boer Jan Hendrik de Boer (19 March 1899 – 25 April 1971) was a Dutch physicist and chemist. De Boer was born in Ruinen, De Wolden, and died in The Hague. He studied at the University of Groningen and was later employed in industry. Together wi ...

in 1925. Heating the tetraiodide with zirconium metal gives zirconium triiodide: :

References

{{iodides Iodides Zirconium(IV) compounds Metal halides