Zirconium(III) iodide is an

inorganic compound In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemist ...

with the

formula In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwee ...

ZrI₃.

Preparation

Like other

group 4 Group 4 may refer to: *Group 4 element, chemical element classification *Group 4 (racing), classification for cars in auto racing and rallying * G4S, formerly Group 4 Securicor, a prominent British security company *IB Group 4 subjects The Group 4 ...

trihalides, zirconium(III) iodide can be prepared from

zirconium(IV) iodide Zirconium(IV) iodide is the chemical compound 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 ...

by high-temperature reduction with

zirconium Zirconium is a chemical element with the symbol Zr and atomic number 40. The name ''zirconium'' is taken from the name of the mineral zircon, the most important source of zirconium. The word is related to Persian '' zargun'' (zircon; ''zar-gun'', ...

metal, although incomplete reaction and contamination of the product with excess metal often occurs. :3 ZrI₄ + Zr → 4 ZrI₃ An alternative is to crystallise zirconium(III) iodide from a solution of zirconium(III) in

aluminium triiodide Aluminium iodide is a chemical compound containing aluminium and iodine. Invariably, the name refers to a compound of the composition , formed by the reaction of aluminium and iodine or the action of on metal. The hexahydrate is obtained f ...

. The solution is prepared by reducing a eutectic solution of ZrI₄ in liquid AlI₃ at a temperature of 280–300 °C with metallic zirconium or aluminium.

Structure and bonding

Zirconium(III) iodide has a lower magnetic moment than is expected for the d¹ metal ion Zr³⁺, indicating non-negligible Zr–Zr bonding. The

crystal structure In crystallography, crystal structure is a description of the ordered arrangement of atoms, ions or molecules in a crystal, crystalline material. Ordered structures occur from the intrinsic nature of the constituent particles to form symmetric pat ...

of zirconium(III) iodide is based on

hexagonal close packing In geometry, close-packing of equal spheres is a dense arrangement of congruent spheres in an infinite, regular arrangement (or lattice). Carl Friedrich Gauss proved that the highest average density – that is, the greatest fraction of space occu ...

iodide An iodide ion is the ion I−. Compounds with iodine in formal oxidation state −1 are called iodides. In everyday life, iodide is most commonly encountered as a component of iodized salt, which many governments mandate. Worldwide, iodine defic ...

ions with one third of the

octahedral In geometry, an octahedron (plural: octahedra, octahedrons) is a polyhedron with eight faces. The term is most commonly used to refer to the regular octahedron, a Platonic solid composed of eight equilateral triangles, four of which meet at ea ...

interstices An interstitial space or interstice is a space between structures or objects. In particular, interstitial may refer to: Biology * Interstitial cell tumor * Interstitial cell, any cell that lies between other cells * Interstitial collagenase, ...

occupied by Zr³⁺ ions. The structure consists of parallel chains of face-sharing octahedra with unequally spaced metal atoms. The Zr–Zr separation alternates between 3.17 Å and 3.51 Å. ZrCl₃, ZrBr₃ and ZrI₃ adopt structures very similar to the β-TiCl₃ structure. In all three ZrX₃ there is some elongation of the octahedra along the metal-metal axis, partly due to metal-metal repulsion, but the elongation is most pronounced in the chloride, moderate in the bromide and negligible in the iodide.

References

{{DEFAULTSORT:Zirconium(Iii) Iodide Zirconium(III) compounds Iodides Metal halides