Skip navigation
Skip navigation

An electron diffraction and bond valence sum study of the space group symmetries and structures of the photocatalytic 1:2 B site ordered A3CoNb2O9 perovskites (A = Ca2+, Sr2+, Ba2+)

Ting, Valeska; Liu, Yun; Withers, Raymond; Noren, Lasse

Description

A careful investigation has been carried out into the space group symmetries, structures and crystal chemistries of the 1:2 B-site ordered triple perovskites A3Co2+Nb5+2O9 (A=Ca2+, Sr2+, Ba2+) using a combination of bond valence sum calculations, powder XRD and electron diffraction. A recent investigation of these compounds by Yin et al. reported a random distribution of Co2+ and Nb5+ ions onto the perovskite B-site positions and hence Pm3̄m (a=ap, subscript p for parent perovskite...[Show more]

dc.contributor.authorTing, Valeska
dc.contributor.authorLiu, Yun
dc.contributor.authorWithers, Raymond
dc.contributor.authorNoren, Lasse
dc.date.accessioned2015-12-13T22:40:05Z
dc.date.available2015-12-13T22:40:05Z
dc.identifier.issn0022-4596
dc.identifier.urihttp://hdl.handle.net/1885/78076
dc.description.abstractA careful investigation has been carried out into the space group symmetries, structures and crystal chemistries of the 1:2 B-site ordered triple perovskites A3Co2+Nb5+2O9 (A=Ca2+, Sr2+, Ba2+) using a combination of bond valence sum calculations, powder XRD and electron diffraction. A recent investigation of these compounds by Yin et al. reported a random distribution of Co2+ and Nb5+ ions onto the perovskite B-site positions and hence Pm3̄m (a=ap, subscript p for parent perovskite sub-structure) space group symmetry for the A=Ba and Sr compounds and a monoclinically distorted variant thereof (although no space group was given) in the case of the A=Ca compound. An electron diffraction study, however, shows that the A=Ba compound occurs in a 1:2 B site ordered trigonal P3̄m1, ah=bp-cp, bh=cp-a p, ch=ap+bp+cp structure type while both the A=Ca and Sr compounds occur at room temperature in monoclinic P121/c1, am=[1̄1̄2]p, bm=[11̄0]p, cm=3[110]p, perovskite-related structure types. The latter monclinic structure type can be described as a modulated variant of the 1:2 B site ordered trigonal P3̄m1 structure type with the additional modulations associated with a b -b-c+ octahedral tilt sequence. Bond valence sum calculations are used to explain why this should be so as well as to provide a useful zeroth-order approximation to the structures of each of the compounds.
dc.publisherAcademic Press
dc.sourceJournal of Solid State Chemistry
dc.subjectKeywords: Approximation theory; Crystal structure; Electron diffraction; X ray powder diffraction; Crystal chemistries; Monoclinic structures; Perovskite; barium; calcium; cobalt; oxygen derivative; strontium; article; chemical bond; correlation analysis; covalent B site ordering; Electron diffraction and bond valence sum study; Triple perovskites
dc.titleAn electron diffraction and bond valence sum study of the space group symmetries and structures of the photocatalytic 1:2 B site ordered A3CoNb2O9 perovskites (A = Ca2+, Sr2+, Ba2+)
dc.typeJournal article
local.description.notesImported from ARIES
local.description.refereedYes
local.identifier.citationvolume177
dc.date.issued2004
local.identifier.absfor030206 - Solid State Chemistry
local.identifier.absfor091201 - Ceramics
local.identifier.ariespublicationMigratedxPub6765
local.type.statusPublished Version
local.contributor.affiliationTing, Valeska, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationLiu, Yun, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationWithers, Raymond, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationNoren, Lasse, College of Physical and Mathematical Sciences, ANU
local.bibliographicCitation.issue7
local.bibliographicCitation.startpage2295
local.bibliographicCitation.lastpage2304
local.identifier.doi10.1016/j.jssc.2004.03.021
local.identifier.absseo970102 - Expanding Knowledge in the Physical Sciences
dc.date.updated2015-12-11T09:53:45Z
local.identifier.scopusID2-s2.0-2942674923
CollectionsANU Research Publications

Download

There are no files associated with this item.


Items in Open Research are protected by copyright, with all rights reserved, unless otherwise indicated.

Updated:  19 May 2020/ Responsible Officer:  University Librarian/ Page Contact:  Library Systems & Web Coordinator