Structural studies of oxygen deficient lanthanide containing double perovskites

Several double perovskite compounds of the type Ba2NdB′O6-δ (B′=Sn4+, Nb5+ and Sb5+) were synthesised. Room temperature neutron diffraction patterns were obtained in order to determine the precise structure of these compounds. It was found that monoclinic Ba2NdSnO5.5 and Ba2NdNbO6 and rhombohedral Ba2NdSbO6 all featured only out-of-phase tilting. The structures of each of these three compounds revealed consistent overbonding of the Nd3+ cations most likely as a result of the significant size difference between the Nd3+ ions and B′ cations. Crown Copyright © 2006