Redetermination of Nd(2)Ti(2)O(7): a non-centrosymmetric structure with perovskite-type slabs

Single crystals of dineodymium(III) dititanium(IV) hepta­oxide, Nd(2)Ti(2)O(7), were synthesized by the flux method and found to belong to the family of compounds with perovskite-type structural motifs. The asymmetric unit contains four Nd, four Ti and 14 O-atom sites. The perovskite-type slabs are stacked parallel to (010) with a thickness corresponding to four corner-sharing TiO(6) octa­hedra. The Nd and Ti ions are displaced from the geometrical centres of respective coordin­ation polyhedra so that the net polarization occurs along the c axis. The investigated crystals were all twinned and have a halved monoclinic unit cell in comparison with the first structure determination of this compound [Scheunemann & Müller-Buschbaum (1975 ▶). J. Inorg. Nucl. Chem. 37, 2261–2263].