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dc.contributor.authorMallick, Subhadip
dc.contributor.authorZhang, Weiguo
dc.contributor.authorBatuk, Maria
dc.contributor.authorGibbs, Alexandra S.
dc.contributor.authorHadermann, Joke
dc.contributor.authorHalasyamani, P. Shiv
dc.contributor.authorHayward, Michael A.
dc.identifier.citationMallick , S , Zhang , W , Batuk , M , Gibbs , A S , Hadermann , J , Halasyamani , P S & Hayward , M A 2022 , ' The crystal and defect structures of polar KBiNb 2 O 7 ' , Dalton Transactions , vol. 51 , no. 5 , pp. 1866-1873 .
dc.identifier.otherORCID: /0000-0002-7012-1831/work/112711396
dc.descriptionFunding: Experiments at the Diamond Light Source were performed as part of the Block Allocation Group award “Oxford/Warwick Solid State Chemistry BAG to probe composition-structure– property relationships in solids” (CY25166). Experiments at the ISIS pulsed neutron facility were supported by a beam time allocation from the STFC (RB 2000148). SM thanks Somerville College for an Oxford Ryniker Lloyd scholarship. ‘PSH and WZ thank the National Science Foundation (DMR-2002319) and Welch Foundation (Grant E-1457) for support.en
dc.description.abstractKBiNb2O7 was prepared from RbBiNb2O7 by a sequence of cation exchange reactions which first convert RbBiNb2O7 to LiBiNb2O7, before KBiNb2O7 is formed by a further K-for-Li cation exchange. A combination of neutron, synchrotron X-ray and electron diffraction data reveal that KBiNb2O7 adopts a polar, layered, perovskite structure (space group A11m) in which the BiNb2O7 layers are stacked in a (0, ½, z) arrangement, with the K+ cations located in half of the available 10-coordinate interlayer cation sites. The inversion symmetry of the phase is broken by a large displacement of the Bi3+ cations parallel to the y-axis. HAADF-STEM images reveal that KBiNb2O7 exhibits frequent stacking faults which convert the (0, ½, z) layer stacking to (½, 0, z) stacking and vice versa, essentially switching the x- and y-axes of the material. By fitting the complex diffraction peak shape of the SXRD data collected from KBiNb2O7 it is estimated that each layer has approximately a 9% chance of being defective-a high level which is attributed to the lack of cooperative NbO6 tilting in the material, which limits the lattice strain associated with each fault.
dc.relation.ispartofDalton Transactionsen
dc.subjectQD Chemistryen
dc.subjectInorganic Chemistryen
dc.titleThe crystal and defect structures of polar KBiNb2O7en
dc.typeJournal articleen
dc.contributor.institutionUniversity of St Andrews. School of Chemistryen
dc.contributor.institutionUniversity of St Andrews. Centre for Designer Quantum Materialsen
dc.description.statusPeer revieweden

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