Discrete and condensed clusters in low Valent Niobium Oxides

3 Discrete and Condensed Clusters in Low Valent Niobium Oxides 

Gunnar Svensson, Jurgen Kohler and Arndt Simon 

The discovery of Ba3Si2Nb20.8O44, the first compound containing discrete Nb60 2 clusters, dates back to the beginning of the seventies, and it took decades until a whole series of reduced oxoniobates were synthesized and characterized (Table 1). The preparations of these oxoniobates have been performed as solid-state reactions 

The characteristic building unit occurring in all low-valent oxoniobates listed in Table 1 is a NbeOii Oe cluster (Fig. la). The Nb-Nb bond distances within the 

A remarkable difference between the oxo cluster and the corresponding halide cluster, i.e. the molecular orbital schemes, becomes obvious when their electronic 

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