Our research focuses on investigation of a new family of compounds - niobium oxohalide framework solids containing octahedral Nb₆ clusters. Formation of clusters via metal-metal bonding is a characteristic feature of many compounds with early transition metals in low oxidation states. The most common structural motif in reduced niobium halides and oxides is the cluster unit [(Nb₆Lⁱ₁₂)L^a₆]^n-.
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In solid state compounds, these [(Nb₆Lⁱ₁₂)L^a₆]^n- cluster units can be present as discrete anions or can be linked to each other by sharing outer or inner ligands to form polymeric structures.
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Using two types of ligands that differ in size and charge will lead to change in symmetry and the charge of these cluster units, which, in turn, is conducive to the formation of new structure types. Indeed, the recently reported first niobium cluster oxohalide ScNb₆Cl₁₃O₃ in which three oxygens occupy inner positions leading to a non-centrosymmetric cluster unit, has a very unusual structure type based on helices of clusters.
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