Mixed Valence and Unusual Germanium Coordination in SrGe8As10, BaGe8As10, and BaGe7P12

Weippert, Valentin; Thanh, Chau; Witthaut, Kristian und Johrendt, Dirk (2020): Mixed Valence and Unusual Germanium Coordination in SrGe8As10, BaGe8As10, and BaGe7P12. In: Inorganic Chemistry, Bd. 59, Nr. 20: S. 15447-15453

Abstract

The new Zintl-compounds AEGe(8)As(10) (AE = Sr, Ba) and BaGe7P12 were synthesized via solid-state reactions, and their structures were determined by single crystal and powder X-ray diffraction. SrGe8As10 and BaGe8As10 crystallize in the space group Croce and show complex 3D networks composed of three different Ge-As motifs and As-As bonds with mixed valence of germanium in the oxidation states +2, + 3, and +4. Mixed valences of germanium +3 and +4 occur in BaGe7P12, which crystallizes in the space group R3 with a 3D network built up of Ge2P6 dumbbells and P-P bonds. An exceptional 6-fold coordinated germanium resides in the center of a GeP6 trigonal antiprism. High temperature X-ray diffraction shows thermal stabilities up to 923-953 K. UV-Vis and resistivity measurements reveal a semiconducting nature with small indirect band gaps between 0.02 and 1.6 eV. Electronic band structure calculations confirm the semiconducting state and indicate covalent bonds within the Ge-Pn polyanions.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Chemie und Pharmazie > Department Chemie
• Themengebiete: 500 Naturwissenschaften und Mathematik > 540 Chemie
• ISSN: 0020-1669
• Sprache: Englisch