The material was first claimed by Ruff and Wallstein who reduced zirconium tetrachloride with aluminium to give impure samples.[4] Subsequently, the problem with aluminium contamination was solved when it was prepared by reduction using zirconium metal:[5]
Zr + 3 ZrCl4 → 4 ZrCl3
When aluminium is used as the reducing agent with zirconium tetrachloride, a series of choloroaluminates are formed, for example [Zr(AlCl4)2(AlCl4)2] and Zr(AlCl4)3.[6]
Since the trihalides, such as zirconium trichloride, are comparatively nonvolatile, contamination can be avoided by using a gaseous reductant. For example, zirconium trichloride can be prepared by reduction of zirconium tetrachloride with hydrogen.[7]
ZrCl4 + ½ H2 → ZrCl3 + HCl
Structure
Some zirconium halides (ZrCl3, ZrBr3, and ZrI3) have structures similar to HfI3. They also have similar space group (P63/mcm) and hexagonal structure with 2 molecules in the cell.[2] The magnetic susceptibility of zirconium trichloride suggests metal-metal interactions of the unpaired electron on each Zr(III) center. The magnetic moment of ZrCl3 (0.4 BM) indicates considerable overlap of metal orbitals.[8]
^ abcZirconium chloride in Linstrom, Peter J.; Mallard, William G. (eds.); NIST Chemistry WebBook, NIST Standard Reference Database Number 69, National Institute of Standards and Technology, Gaithersburg (MD) (retrieved 2014-06-23)
^Ruff, Otto; Wallstein, Richard (1923). "Reduktion anorganischer Halogenide III.1) Die Reduktion des Zirkontetrachlorids". Zeitschrift für anorganische und allgemeine Chemie. 128: 96–116. doi:10.1002/zaac.19231280110.
^Hoffman, David M.; Lee, Samkeun (1992). "Synthesis of pyridine complexes of zirconium(III) chloride and the apparent oxidation to zirconium(IV) by a nitrile". Inorganic Chemistry. 31 (13): 2675. doi:10.1021/ic00039a002.
^Larsen, E. M.; Moyer, James W.; Gil-Arnao, Francisco.; Camp, Michael J. (1974). "Synthesis of crystalline zirconium trihalides by reduction of tetrahalides in molten aluminum halides. Nonreduction of hafnium". Inorganic Chemistry. 13 (3): 574. doi:10.1021/ic50133a015.
^Newnham, I. E.; Watts, J. A. (1960). "The Preparation of the Anhydrous Zirconium Trihalides". Journal of the American Chemical Society. 82 (9): 2113. doi:10.1021/ja01494a006.
