Zirconium clusters

Centered Zirconium Clusters Mixed-halide Systems... 

In this article we will review some recent results in mixed-halide zirconium cluster chemistry, which were developed starting from John Corbetts protocols. 

Of course, the chemistry of zirconium cluster phases has been well described and reviewed in the literature [1-4]. Apart from a very few examples, mostly in the binary halides, almost all reduced zirconium halides contain octahedra of zirconium atoms centred on an interstitial atom Z. Several possible and experimentally realized Z include H, Be-N, K, Al-P, and the transition metals Mn-Ni. All these compounds have the general formula Ax"[(Zr6Z)Xi2X[J], with a " = alkali or alkaline earth metal cation, X=C1 Br or I, X =inner edge-bridging halide [5], X =outer exo-bonded halide, and 0[Pg.61]

Mixed-Chloride-lodide Zirconium Cluster Phases with a 6 12-Metal Halide Ratio 63 5.3... 

With boron and an appropriate amount of some sort of alkaline metal halide present in the starting materials for the solid-state reactions, then we obtain zirconium cluster materials belonging to the 6-14 family. Single-crystal X-ray data of products from iodine-rich reactions were used to determine the crystal structures of Na[(Zr6B)Cl3.87(5)lio.i3], and Cs[(Zr6B)Cl2.i6(5)lii.84] [21]. Both phases... 

Similar to the mixed-halide (Cl, I) 6-13 system, where more chlorine-rich reactions produced a new structure type, materials with an unprecedented zirconium cluster structure are obtained in the Na-Zr-(C1/I)-B system (also with. other cations, see below), when larger Cl/I ratios are used than above. Compounds characterized are Na[(Zr6B)(Cl,I)i4] and Ao.5[(Zr6B)(Cl,I)i4] (with A = Ca, Sr, Ba) [25, 26]. Single crystals of the cubic Na[(Zr6B)Clio.94(i)l3.o6] and... 

It is interesting to note that zirconium cluster iodides only exist in the 6-12 and 6-14 type family. Therefore, this double salt is the first member of a 6-15 type family of compounds in which iodine atoms participate in the inter-cluster connectivity. 

Mixed Chloride-Iodide Zirconium Cluster Phases with a 6 18 Metal Halide Ratio -Products from Solid-state Reactions... 

Table IV lists specific examples of compounds related through this form of dimensional reduction, By far, the majority of these are zirconium chloride and iodide phases, in which case lower main group and even transition metals have been found to incorporate as interstitial atoms. A few analogues are known with hafnium (135), and very recently it has been shown that nitrogen can be substituted for carbon in tungsten chloride clusters adopting the centered trigonal-prismatic geometry (see Fig. 2) (32). It is hoped that a variability similar to that exposed for the octahedral zirconium clusters will be attainable for such trigonal-prismatic cluster phases.

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