Synthesis and structural characterization of A{sub 3}In{sub 2}Ge{sub 4} and A{sub 5}In{sub 3}Ge{sub 6} (A=Ca, Sr, Eu, Yb)-New intermetallic compounds with complex structures, exhibiting Ge-Ge and In-In bonding
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716 (United States)
Reported are the synthesis and the structural characterization of four new polar intermetallic phases, which exist only with mixed alkaline-earth and rare-earth metal cations in narrow homogeneity ranges. (Sr{sub 1-x}Ca{sub x}){sub 5}In{sub 3}Ge{sub 6} and (Eu{sub 1-x}Yb{sub x}){sub 5}In{sub 3}Ge{sub 6} (x{approx}0.7) crystallize in the orthorhombic space group Pnma with two formula units per unit cell (own structure type, Pearson symbol oP56). The lattice parameters are as follows: a=13.109(3)-13.266(3) A, b=4.4089(9)-4.4703(12) A, and c=23.316(5)-23.557(6) A. (Sr{sub 1-x}Ca{sub x}){sub 3}In{sub 2}Ge{sub 4} and (Sr{sub 1-x}Yb{sub x}){sub 3}In{sub 2}Ge{sub 4} (x{approx}0.4-0.5) adopt another novel monoclinic structure-type (space group C2/m, Z=4, Pearson symbol mS36) with lattice parameters in the range a=19.978(2)-20.202(2) A, b=4.5287(5)-4.5664(5) A, c=10.3295(12)-10.3447(10) A, and {beta}=98.214(2)-98.470(2){sup o}, depending on the metal cations and their ratio. The polyanionic sub-structures in both cases are based on chains of InGe{sub 4} corner-shared tetrahedra. The A{sub 5}In{sub 3}Ge{sub 6} structure (A=Sr/Ca or Sr/Yb) also features Ge{sub 4} tetramers, and isolated In atoms in nearly square-planar environment, while the A{sub 3}In{sub 2}Ge{sub 4} structure (A=Sr/Ca or Eu/Yb) contains zig-zag chains of In and Ge strings with intricate topology of cis- and trans-bonds. The experimental results have been complemented by tight-binding linear muffin-tin orbital (LMTO) band structure calculations. - Graphical abstract: The anion sub-network of A{sub 5}In{sub 3}Ge{sub 6} is based upon tetrahedral [InGe{sub 4}] chains, Ge{sub 4} tetramers isosteric with 1,3-cis-butadiene, and distorted square-planar [InGe{sub 4}] fragments. The structure of A{sub 3}In{sub 2}Ge{sub 4} is a combination of infinite Ge chains with cis- and trans-bonds in a complex (tttctc){sub n} pattern, tetrahedral [InGe{sub 4}] chains, and In zig-zag chains.
- OSTI ID:
- 21421509
- Journal Information:
- Journal of Solid State Chemistry, Vol. 183, Issue 6; Other Information: DOI: 10.1016/j.jssc.2010.03.036; PII: S0022-4596(10)00126-X; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CALCIUM ALLOYS
ELECTRONIC STRUCTURE
EUROPIUM ALLOYS
GERMANIUM ALLOYS
INDIUM ALLOYS
INTERMETALLIC COMPOUNDS
LATTICE PARAMETERS
MONOCLINIC LATTICES
ORTHORHOMBIC LATTICES
SPACE GROUPS
STRONTIUM ALLOYS
SYNTHESIS
X-RAY DIFFRACTION
YTTERBIUM ALLOYS
ALLOYS
COHERENT SCATTERING
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DIFFRACTION
RARE EARTH ALLOYS
SCATTERING
SYMMETRY GROUPS