open access

https://hdl.handle.net/2115/81629

Flux Crystal Growth, Structure, and Optical Properties of the New Germanium Oxysulfide La-4(GeS2O2)(3)

英語

2020-06-03

American Chemical Society

Crystal growth & design

20(6)

4054-4061

Single crystals of a new germanium oxysulfide La-4(GeS2O2)(3) were grown out of a BaCl2-CaCl2 eutectic flux, and the crystal structure was determined via single-crystal X-ray diffraction. Ivory-white La-4(GeS2O2)(3) crystallizes in the centrosymmetric space group R (3) over bar with lattice constants of a = b = 16.8283(3) angstrom and c = 8.4140(2) angstrom. La-4(GeS2O2)(3) exhibits complex three- dimensional anion order in the framework composed of unusual GeS2O2 tetrahedra and three types of La-centered polyhedra. Moreover, the triangular arrangement of the GeS2O2 tetrahedra around a columnar structure of alternating face-sharing LaO12 and LaS6O6 units resembles that of GeO4 tetrahedra in the apatite germanate La-9.33(GeO4)(6)O-2, which features face-sharing LaO9 columns. The combination of UV-vis absorption measurements and first-principles calculations revealed the existence of an indirect optical band gap (E-g = 3.67 eV) between the valence band maximum composed of S 3p orbitals and the conduction band minimum composed of La 3d, La 4f, S 3p, and Ge 4s orbitals.

学術雑誌論文

Accepted Manuscript

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Crystal Growth & Design, copyright c American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/10.1021/acs.cgd.0c00332.

1528-7483