Title

Structural, Optical, and Magnetic Properties of Na8Eu2(Si2S6)2 and Na8Eu2(Ge2S6)2: Europium(II) Quaternary Chalcogenides That Contain an Ethane-Like (Si2S6)6- or (Ge2S6)6- Moiety

Abstract

Two isostructural europium(II) quaternary chalcogenides, Na8Eu2(Si2S6)2, 1, and Na8Eu2(Ge2S6)2, 2, containing an ethane-like (Si2S6)6- or (Ge2S6)6- moiety have been synthesized by employing the polychalcogenide molten flux method. Single-crystal X-ray diffraction reveals that both compounds crystallize in the C2/m space group, and their structures contain layers of {[Na2Eu2(Si2S6)2]6-} or {[Na2Eu2(Ge2S6)2]6-} anions held together by six interlayer sodium cations to yield {Na6[Na2Eu2(Si2S6)2]} and {Na6[Na2Eu2(Ge2S6)2]}. Compound 2 is a semiconductor with an optical band gap of 2.15(2) eV. The temperature dependence of the magnetic susceptibility indicates that compounds 1 and 2 are paramagnetic with μeff=7.794(1) μB per Eu and g=1.964(1) for 1 and μeff=8.016(1) μB per Eu and g=2.020(1) for 2, moments that are in good agreement with the europium(II) spin-only moment of 7.94 μB. The europium-151 Mössbauer isomer shift of 2 confirms the presence of europium(II) cations with an electronic configuration between [Xe]4f6.81 and 4f76s0.32.

Department(s)

Chemistry

International Standard Serial Number (ISSN)

224596

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2015 Academic Press Inc., All rights reserved.


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