title: Atomic and domain structure of the low-temperature phase of barium metagermanate (BaGeO3).
abstract: The crystal structure of the low-temperature form of barium metagermanate (BaGeO3) has been determined from laboratory X-ray powder diffraction data collected at 298.5 (5) K. The structure was found to consist of alternating layers of Ba cations and [GeO3]3 rings, and is closely related to pseudo-wollastonite. The rings show a twofold positional disorder owing to stacking faults. The stacking is not random, but can be rationalized by a twinning mechanism mapping the two non-congruent enantiomorphic polytypes of the structure onto each other. This model also explains the diffuse scattering and twinning observed in SAED and HRTEM, as well as the size and strain-like broadening effects found in the XRPD pattern.
authors.affiliation: Institute of Mineralogy and Petrography, University of Innsbruck, Innrain 52, A-6020 Innsbruck, Austria. daniel.toebbens@uibk.ac.at
authors.forename: Daniel Maria
authors.initials: DM
authors.lastname: Többens
authors.forename: Volker
authors.initials: V
authors.lastname: Kahlenberg
authors.forename: Christian
authors.initials: C
authors.lastname: Gspan
authors.forename: Gerald
authors.initials: G
authors.lastname: Kothleitner
mesh_terms: D001464:Barium / Q000737:chemistry*; D005857:Germanium / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D008958:Models, Molecular; D010100:Oxygen / Q000737:chemistry*; D033362:Powder Diffraction; D012680:Sensitivity and Specificity; D013696:Temperature
chemical_list: C516499:barium metagermanate; D005857:Germanium; D001464:Barium; D010100:Oxygen