THE LAYERED COMPOUND TL2NBO2PO4 - SYNTHESIS AND CRYSTAL-STRUCTURE

A new layered compound, Tl2NbO2PO4, has been isolated. It crystallizes in the rhombohedral system, space group R3̄. The cell parameters are a = 8.746(2)Å, c = 44.753(7)Å. Z = 18. Its structure has been determined from 990 independent reflections, with I ≥ 3σ(I), collected on a CAD4 automated diffractometer. The final R index and weighted Rω index are 0.034 and 0.032, respectively. This structure is built up from layers of NbO6 octahedra and PO4 tetrahedra sharing corners. The Tl ions are located in the interlayer spaces. © 1993 Academic Press, Inc.