Calcium Substitution in Rare-earth Metal Germanides with the Gd5Si4 Type Structure

Date
2022-02-23
Journal Title
Journal ISSN
Volume Title
Publisher
Journal of Inorganic and General Chemistry
Abstract
An extended series of rare-earth metal calcium germanides have been synthesized and structurally characterized. The compounds have the general formula RE5−xCaxGe4 (1.5<x<3.6; RE=rare-earth metal; Ce, Nd, Sm, Tb−Lu) and their structures have been established from single-crystal X-ray diffraction methods. They crystallize with the Gd5Si4-type in the orthorhombic space group Pnma (No. 62; Z=4; Pearson symbol oP36), where the germanium atoms are interconnected into two kinds of Ge2-dimers, formally [Ge2]6−. These studies show that Ca can be successfully incorporated into the host RE5Ge4 structure, whereby trivalent rare-earth metal atoms can be substituted by divalent calcium atoms. Rare-earth metal and calcium atoms are arranged in distorted trigonal prisms and cubes, centered by either Ge or Ca atoms. On one of the metal sites, the substitution is preferential and in 9 out of the 10 refined structures, the Wyckoff site 4c is found almost exclusively occupied by Ca. On the other two metal sites the substitution patterns appear to be governed by the mismatch between the size of the RE3+ and Ca2+ ions. This work further demonstrates the ability for the Gd5Si4 structure type to accommodate the substitution of a non-magnetic element while maintaining the global structural integrity.
Description
This is the peer reviewed version of the following article: Suen, Nian‐Tzu, and Svilen Bobev. “Calcium Substitution in Rare‐earth Metal Germanides with the Gd 5 Si 4 Type Structure.” Zeitschrift Für Anorganische Und Allgemeine Chemie, February 23, 2022. https://doi.org/10.1002/zaac.202200016, which has been published in final form at https://doi.org/10.1002/zaac.202200016. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited. This article will be embargoed until 02/23/2023.
Keywords
Germanides, Crystal structure, Zintl phases, Lanthanides
Citation
Suen, Nian‐Tzu, and Svilen Bobev. “Calcium Substitution in Rare‐earth Metal Germanides with the Gd 5 Si 4 Type Structure.” Zeitschrift Für Anorganische Und Allgemeine Chemie, February 23 2022. https://doi.org/10.1002/zaac.202200016.