ChemInform Abstract: New Twists on the Perovskite Theme: Crystal Structures of the Elusive Phases R and S of NaNbO₃.

Abstract

New Twists on the Perovskite Theme: Crystal Structures of the Elusive Phases R and S of NaNbO3. -The crystal structure of NaNbO3 is determined in the temperature range between 360 and 520°C by high-resolution neutron and synchrotron X-ray powder diffraction, supported by DFT computations. New structural models are proposed for the elusive phases S (stable between 480 and 510°C) and R (370-470°C). A unique model for phase S is elucidated, having a 2 x 2 x 4 superlattice of the aristotype perovskite structure (space group Pmmn). This structure features a new example of an octahedral tilt system in a perovskite type compound. Two possible structural models for phase R are determined. -(PEEL, M. D.; THOMPSON, S. P.; DAOUD-ALADINE, A.; ASHBROOK, S. E.; LIGHTFOOT*, P.; Inorg. Chem. 51 (2012) 12, 6876-6889, http://dx.doi.org/10.1021/ic3006585 ; EaStChem, Sch. Chem.,