Syntheses, and crystal and electronic structures of the new Zintl phases Na{sub 2}ACdSb{sub 2} and K{sub 2}ACdSb{sub 2} (A=Ca, Sr, Ba, Eu, Yb): Structural relationship with Yb{sub 2}CdSb{sub 2} and the solid solutions Sr{sub 2-x}A{sub x}CdSb{sub 2}, Ba{sub 2-x}A{sub x}CdSb{sub 2} and Eu{sub 2-x}Yb{sub x}CdSb{sub 2}

Journal Article · Tue Feb 15 00:00:00 EST 2011 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2010.12.015· OSTI ID:21494201

Saparov, Bayrammurad; Saito, Maia ^[1]; Bobev, Svilen ^[1]

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1. Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716 (United States)

Presented are the details of the syntheses, crystal and electronic structures of a new family of Zintl phases Na{sub 2}ACdSb{sub 2} and K{sub 2}ACdSb{sub 2} (A=Ca, Sr, Ba, Eu, Yb), as well as the solid solutions Sr{sub 2-x}A{sub x}CdSb{sub 2}, Ba{sub 2-x}A{sub x}CdSb{sub 2} and Eu{sub 2-x}Yb{sub x}CdSb{sub 2}. The structures of Na{sub 2}ACdSb{sub 2} and K{sub 2}ACdSb{sub 2} (A=Ca, Sr, Ba, Eu, Yb) were determined to be of a new type with the non-centrosymmetric space group Pmc2{sub 1} (no. 26), Pearson symbol oP12, with lattice parameters a=4.684(1)-4.788(1) A; b=9.099(3)-9.117(2) A; c=7.837(1)-8.057(2) A for the Na{sub 2}ACdSb{sub 2} series, and a=4.6637(9)-5.0368(8) A; b=9.100(2)-9.8183(15) A; and c=7.7954(15)-8.4924(13) A for K{sub 2}ACdSb{sub 2}, respectively. The solid solutions Sr{sub 2-x}A{sub x}CdSb{sub 2}, Ba{sub 2-x}A{sub x}CdSb{sub 2} and Eu{sub 2-x}Yb{sub x}CdSb{sub 2} (x{approx}1) are isostructural and isoelectronic to the recently reported Yb{sub 2}CdSb{sub 2} (space group Cmc2{sub 1} (no. 36), Pearson symbol cP20). All discussed structures are based upon CdSb{sub 2}{sup 4-} polyanionic layers, similar to the ones observed in Yb{sub 2}CdSb{sub 2}, with various alkali- and/or alkaline-earth cations coordinated to them. Magnetic susceptibility and Seebeck coefficient measurements on selected Eu{sub 2-x}Yb{sub x}CdSb{sub 2} samples, taken at low temperatures up to 300 K, are also reported. -- Graphical abstract: The quaternary Zintl phases Na{sub 2}ACdSb{sub 2} and K{sub 2}ACdSb{sub 2} (A=Ca, Sr, Ba, Eu, Yb) with novel layered structures have been synthesized for the first time and structurally characterized by single-crystal X-ray diffraction. Reported as well are the results from crystallographic and property studies of the closely related solid solutions Sr{sub 2-x}A{sub x}CdSb{sub 2}, Ba{sub 2-x}A{sub x}CdSb{sub 2} (x{approx}1), and Eu{sub 2-x}Yb{sub x}CdSb{sub 2} (1<x{<=}2). Display Omitted Research highlights: {yields} Na{sub 2}ACdSb{sub 2} and K{sub 2}ACdSb{sub 2} (A=Ca, Sr, Ba, Eu, Yb) are new quaternary Zintl phases. {yields} Sr{sub 2-x}A{sub x}CdSb{sub 2}, Ba{sub 2-x}A{sub x}CdSb{sub 2} (x{approx}1), and Eu{sub 2-x}Yb{sub x}CdSb{sub 2} (1<x<2) are solid solutions. {yields} Both structures are layered, based on corner-shared CdSb{sub 4} tetrahedra. {yields} Eu{sub 2-x}Yb{sub x}CdSb{sub 2} (1<x<2) exhibit high Seebeck coefficient (217 {mu}V/K at RT).

• OSTI ID: 21494201
• Journal Information: Journal of Solid State Chemistry, Vol. 184, Issue 2; Other Information: DOI: 10.1016/j.jssc.2010.12.015; PII: S0022-4596(10)00561-X; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANTIMONY COMPOUNDS
BARIUM COMPOUNDS
CADMIUM COMPOUNDS
CALCIUM COMPOUNDS
CRYSTALLOGRAPHY
ELECTRONIC STRUCTURE
EUROPIUM COMPOUNDS
LATTICE PARAMETERS
LAYERS
MAGNETIC SUSCEPTIBILITY
MONOCRYSTALS
ORTHORHOMBIC LATTICES
POTASSIUM COMPOUNDS
SODIUM COMPOUNDS
SOLID SOLUTIONS
SPACE GROUPS
STRONTIUM COMPOUNDS
SYNTHESIS
TEMPERATURE RANGE 0400-1000 K
THERMOELECTRIC PROPERTIES
X-RAY DIFFRACTION
YTTERBIUM COMPOUNDS
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
COHERENT SCATTERING
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CRYSTALS
DIFFRACTION
DISPERSIONS
ELECTRICAL PROPERTIES
HOMOGENEOUS MIXTURES
MAGNETIC PROPERTIES
MIXTURES
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
SCATTERING
SOLUTIONS
SYMMETRY GROUPS
TEMPERATURE RANGE