Pb sub(2.85)Ba sub(2.15)Fe sub(4)SnO sub(13): A new member of the A sub(n)B sub(n)O sub(3n-2) anion-deficient perovskite-based homologous series

• Published in: Journal of solid state chemistry 2011-12, Vol.184 (12), p.3150-3157
• Main Authors: Korneychik, Oleg E, Batuk, Maria, Abakumov, Artem M, Hadermann, Joke, Rozova, Marina G, Sheptyakov, Denis V, Pokholok, Konstantin V, Filimonov, Dmitry S, Antipov, Evgeny V
• Format: Article
• Language: English
• Subjects: Mossbauer spectroscopy; Perovskites; Planes; Pyramids; Shear; Solid state; Tin; Unit cell
• ISSN: 0022-4596
• DOI: 10.1016/j.jssc.2011.09.029

Pb sub(2.85)Ba sub(2.15)Fe sub(4)SnO sub(13), a new n=5 member of the anion-deficient perovskite based A sub(n)B sub(n)O sub(3n-2) (A=Pb, Ba, B=Fe, Sn) homologous series, was synthesized by the solid state method. The crystal structure of Pb sub(2.85)Ba sub(2.15)Fe sub(4)SnO sub(13) was investigated using a combination of neutron powder diffraction, electron diffraction, high angle annular dark field scanning transmission electron microscopy and Mossbauer spectroscopy. It crystallizes in the Ammm space group with unit cell parameters a=5.7990(1) a, b=4.04293(7) a and c=26.9561(5) a. The Pb sub(2.85)Ba sub(2.15)Fe sub(4)SnO sub(13) structure consists of quasi two-dimensional perovskite blocks separated by 1/2[110](1 Delta 01) sub(p) crystallographic shear (CS) planes. The corner-sharing FeO sub(6) octahedra at the CS planes are transformed into edge-sharing FeO sub(5) distorted tetragonal pyramids. The octahedral positions in the perovskite blocks between the CS planes are jointly taken up by Fe and Sn, with a preference of Sn towards the position at the center of the perovskite block. The chains of FeO sub(5) pyramids and (Fe,Sn)O sub(6) octahedra of the perovskite blocks delimit six-sided tunnels at the CS planes occupied by double chains of Pb atoms. The compound is antiferromagnetically ordered below T sub(N)=368+/-15 K.