Synthesis and cation distribution in the new bismuth oxyhalides with the Sillén–Aurivillius intergrowth structures. Issue 47 (10th November 2015)

• Record Type: Journal Article
• Authors: Charkin, Dmitri O.; Akinfiev, Victor S.; Alekseeva, Anastasia M.; Batuk, Maria; Abakumov, Artem M.; Kazakov, Sergey M.
• Is Part Of: Dalton transactions. Volume 44:Issue 47(2015)
• Page Start: 20568
• Page End: 20576
• Publication Date: 2015-11-10
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c5dt02620b
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : Extensive synthetic and structural exploration of a new family of Sillen–Aurivillius intergrowth bismuth oxyhalides reveals clear size preferences for the alkaline earth cations and suggest a new stability criterion for complex intergrowth structures. Abstract : About 20 new compounds with the Sillén–Aurivillius intergrowth structure, Me 1 Me 2 Bi3 Nb2 O11 X (Me 1 = Pb, Sr, Ba; Me 2 = Ca, Sr, Ba; X = Cl, Br, I), have been prepared. They are composed of stacking of [ANb2 O7 ] perovskite blocks, fluorite-type [M2 O2 ] blocks and halogen sheets. The cation distribution between the fluorite and perovskite layers has been studied for Ba2 Bi3 Nb2 O11 I, Ca1.25 Sr0.75 Bi3 Nb2 O11 Cl, BaCaBi3 Nb2 O11 Br and Sr2 Bi3 Nb2 O11 Cl. The smaller Me cations tend to reside in the perovskite block while the larger ones are situated in the fluorite-type block. The distribution of the elements was confirmed for BaCaBi3 Nb2 O11 Br using energy dispersive X-ray analysis combined with scanning transmission electron microscopy (STEM-EDX). An electron diffraction study of this compound reveals a local symmetry lowering caused by weakly correlated rotation of NbO6 octahedra. Based on our findings, we suggest a new stability criterion for mixed-layer structures, which is that net charges of any two consecutive layers do not compensate for each other and only the whole layer sequence is electroneutral.