Zirconium -iodide zrl

Lead iodide (Pbl) lodosilylidyne (SiI) Strontiun iodide (Sri) Titanlun iodide (Til) Zirconium iodide (Zrl)... 

Eleven different species were distinguished during an effusion equilibrium study of the non-stoicheiometric zirconium iodides.240 Enthalpy and entropy changes for the disproportionation reactions leading to these species were evaluated as were the heats of formation of Zrl (n = 4, 3.2, 3.17, 3, 2.82, or 2.5). A distorted tetrahedral co-ordination of the fluorines around hafnium in HfF4 appears likely according to... 

In 1925 van Arkel and de Boer [19.2] published their first report about their famous method of producing metals in pure form by thermal decomposition of the metal iodide. In the zirconium case, impure zirconium metal is placed in an evacuated container and treated at 300°C with iodine vapor to form Zrl,. This tetraiodide is diffused to an electrically heated filament of tungsten or zirconium wire. At 1300-1400°C the zirconium iodide is dissociated to iodine gas and very ductile zirconium metal. From 1925 to 1945 the iodide process was the method used for obtaining pure, ductile zirconium metal. 

Iodide compounds are not very stable, so heating them can result in an easy recapture of the metal elements in the compound. For example, the van Arkel-de-Boer process (or crystal bar process) is used to purify zirconium. This is done by passing the heated gas (Zrl ) over a white hot tungsten filament, and over time the metals form on the tungsten. 

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