Layer structure: The oxides A3Ti5MO14

Five new oxides, K₃Ti₅MO₁₄, Rb₃Ti₅MO₁₄ (M = Ta, Nb), and Tl₃Ti₅NbO₁₄, have been synthesized. The structure of these oxides consists of octahedral layers similar to those observed for Na₂Ti₃O₇ and held together by monovalent ions; the sheets consist of blocks of 2 × 3 edge-sharing octahedra, which are then joined to each other by the corners of the octahedra. The relative disposition of the layers is similar to that observed for Tl₂Ti₄O₉. These oxides can be considered as the member n = 3 of a series of closely related structures with formula A_nB_2nO_4n+2, where n indicates the number of octahedra which determines the width of the blocks of 2 × n octahedra.