The Crystal Structure of α-K3AlF6: Elpasolites and Double Perovskites with Broken Corner-Sharing Connectivity of the Octahedral Framework

被引:29
作者
Abakumov, Artem M. [1 ,3 ]
King, Graham [2 ]
Laurinavichute, Veronika K. [3 ]
Rozova, Marina G. [3 ]
Woodward, Patrick M. [2 ]
Antipov, Evgeny V. [3 ]
机构
[1] Univ Antwerp, EMAT, B-2020 Antwerp, Belgium
[2] Ohio State Univ, Dept Chem, Columbus, OH 43210 USA
[3] Moscow MV Lomonosov State Univ, Dept Chem, Moscow 119992, Russia
关键词
GROUP-THEORETICAL ANALYSIS; PHASE-TRANSITIONS; BOND-VALENCE; DIFFRACTION; K3MOO3F3; ALKALI; VII);
D O I
10.1021/ic9013043
中图分类号
O61 [无机化学];
学科分类号
070301 ; 081704 ;
摘要
The crystal structure of alpha-K3AlF6 was solved and refined from a combination of powder X-ray and neutron diffraction data (a = 18.8385(3)angstrom, c = 33.9644(6)angstrom, S.G. l4(1)/a, Z = 80, R-P(X-ray) = 0.037, R-P(neutron) = 0.053). The crystal structure is of the A(2)BB'X-6 elpasolite type with the a = b approximate to a(e)root 5, c = 4a(e) superstructure (a(e), parameter of the elpasolite subcell) and rock-salt-type ordering of the K and Al cations over the B and B' positions, respectively. The remarkable feature of alpha-K3AlF6 is a rotation of 2/5 of the AlF6 octahedra by similar to pi/4 around one of the crystal axes of the elpasolite subcell, coinciding with the 4-fold symmetry axes of the AlF6 octahedra. The rotation of the AlF6 octahedra replaces the corner-sharing between the K and Al polyhedra by edge-sharing, resulting in an increase of coordination numbers of the K cations at the B positions up to 7 and 8. Due to significant deformations of the K polyhedra, the comer-sharing connectivity of the octahedral elpasolite framework is broken and the rotations of the AlF6 octahedra do not have a cooperative character. Elpasolites and double perovskites with similar structural organization are discussed. The difference in ionic radii of the B and B' cations as well as the tolerance factor are proposed to be the parameters governing the formation of elpasolites and double perovskites with broken comer-sharing connectivity of the octahedral framework.
引用
收藏
页码:9336 / 9344
页数:9
相关论文
共 25 条
[1]   Phase transitions in K3A1F6 [J].
Abakumov, AM ;
Rossell, MD ;
Alekseeva, AM ;
Vassiliev, SY ;
Mudrezova, SN ;
Van Tendeloo, G ;
Antipov, EV .
JOURNAL OF SOLID STATE CHEMISTRY, 2006, 179 (02) :421-428
[2]   The crystal structure of Ca3ReO6 [J].
Abakumov, AM ;
Shpanchenko, RV ;
Antipov, EV ;
Lebedev, OI ;
VanTendeloo, G .
JOURNAL OF SOLID STATE CHEMISTRY, 1997, 131 (02) :305-309
[3]   Relationship between bond valence and bond softness of alkali halides and chalcogenides [J].
Adams, S .
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE CRYSTAL ENGINEERING AND MATERIALS, 2001, 57 (57) :278-287
[4]  
Aleksandrov K. S., 1981, Soviet Physics - Crystallography, V26, P612
[5]   B-CATION ARRANGEMENTS IN DOUBLE PEROVSKITES [J].
ANDERSON, MT ;
GREENWOOD, KB ;
TAYLOR, GA ;
POEPPELMEIER, KR .
PROGRESS IN SOLID STATE CHEMISTRY, 1993, 22 (03) :197-233
[6]   THE CRYSTAL-STRUCTURES OF BA2LARUO6 AND CA2LARUO6 [J].
BATTLE, PD .
MATERIALS RESEARCH BULLETIN, 1981, 16 (04) :397-405
[7]   Preparation, structure, and magnetic studies of a new Sr11Re4O24 double oxide [J].
Bramnik, KG ;
Miehe, G ;
Ehrenberg, H ;
Fuess, H ;
Abakumov, AM ;
Shpanchenko, RV ;
Pomjakushin, VY ;
Balagurov, AM .
JOURNAL OF SOLID STATE CHEMISTRY, 2000, 149 (01) :49-55
[8]   An electron diffraction and XRPD study of superlattice ordering in the elpasolite-related oxyfluoricle K3MoO3F3 [J].
Brink, FJ ;
Withers, RL ;
Friese, K ;
Madariaga, G ;
Norén, L .
JOURNAL OF SOLID STATE CHEMISTRY, 2002, 163 (01) :267-274
[9]   BOND-VALENCE PARAMETERS OBTAINED FROM A SYSTEMATIC ANALYSIS OF THE INORGANIC CRYSTAL-STRUCTURE DATABASE [J].
BROWN, ID ;
ALTERMATT, D .
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE, 1985, 41 (AUG) :244-247
[10]   FOX, 'free objects for crystallography':: a modular approach to ab initio structure determination from powder diffraction [J].
Favre-Nicolin, V ;
Cerny, R .
JOURNAL OF APPLIED CRYSTALLOGRAPHY, 2002, 35 :734-743