Structures of Three Alkaline-Earth Metal Germanides Refined from Single-Crystal X-ray Diffraction Data
The calcium- and strontium- alumo-germanides Sr<i><sub>x</sub></i>Ca<sub>1–<i>x</i></sub>Al<sub>2</sub>Ge<sub>2</sub> (<i>x</i> ≈ 0.4) and SrAl<sub>2</sub>Ge<sub>2</sub> have been synthesized...
| Main Authors: | , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2022-11-01
|
| Series: | Chemistry |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2624-8549/4/4/94 |
| _version_ | 1827641360384000000 |
|---|---|
| author | Nian-Tzu Suen Svilen Bobev |
| author_facet | Nian-Tzu Suen Svilen Bobev |
| author_sort | Nian-Tzu Suen |
| collection | DOAJ |
| description | The calcium- and strontium- alumo-germanides Sr<i><sub>x</sub></i>Ca<sub>1–<i>x</i></sub>Al<sub>2</sub>Ge<sub>2</sub> (<i>x</i> ≈ 0.4) and SrAl<sub>2</sub>Ge<sub>2</sub> have been synthesized and structurally characterized. Additionally, a binary calcium germanide CaGe has also been identified as a byproduct. All three crystal structures have been established from single-crystal X-ray diffraction methods and refined with high accuracy and precision. The binary CaGe crystallizes with a CrB-type structure in the orthorhombic space group <i>Cmcm</i> (no. 63; <i>Z</i> = 4; Pearson symbol <i>oC</i>8), where the germanium atoms are interconnected into infinite zigzag chains, formally [Ge]<sup>2−</sup>. The calcium atoms are arranged in monocapped trigonal prisms, centered by Ge atoms. Sr<i><sub>x</sub></i>Ca<sub>1−<i>x</i></sub>Al<sub>2</sub>Ge<sub>2</sub> (<i>x</i> ≈ 0.4) and SrAl<sub>2</sub>Ge<sub>2</sub> have been confirmed to crystallize with a CaAl<sub>2</sub>Si<sub>2</sub>-type structure in the trigonal space group <i>P</i><inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mover accent="true"><mn>3</mn><mo>¯</mo></mover></semantics></math></inline-formula><i>m</i>1 (no. 164; <i>Z</i> = 1; Pearson symbol <i>hP</i>5), where the germanium and aluminum atoms form puckered double-layers, formally [Al<sub>2</sub>Ge<sub>2</sub>]<sup>2−</sup>. The calcium atoms are located between the layers and reside inside distorted octahedra of Ge atoms. All presented structures have a valence electron count satisfying the octet rules (e.g., Ca<sup>2+</sup>Ge<sup>2−</sup> and Ca<sup>2+</sup>[Al<sub>2</sub>Ge<sub>2</sub>]<sup>2−</sup>) and can be regarded as Zintl phases. |
| first_indexed | 2024-03-09T17:12:51Z |
| format | Article |
| id | doaj.art-ec4a396b687c448e932410434c0a979e |
| institution | Directory Open Access Journal |
| issn | 2624-8549 |
| language | English |
| last_indexed | 2024-03-09T17:12:51Z |
| publishDate | 2022-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Chemistry |
| spelling | doaj.art-ec4a396b687c448e932410434c0a979e2023-11-24T13:58:35ZengMDPI AGChemistry2624-85492022-11-01441429143810.3390/chemistry4040094Structures of Three Alkaline-Earth Metal Germanides Refined from Single-Crystal X-ray Diffraction DataNian-Tzu Suen0Svilen Bobev1Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USADepartment of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USAThe calcium- and strontium- alumo-germanides Sr<i><sub>x</sub></i>Ca<sub>1–<i>x</i></sub>Al<sub>2</sub>Ge<sub>2</sub> (<i>x</i> ≈ 0.4) and SrAl<sub>2</sub>Ge<sub>2</sub> have been synthesized and structurally characterized. Additionally, a binary calcium germanide CaGe has also been identified as a byproduct. All three crystal structures have been established from single-crystal X-ray diffraction methods and refined with high accuracy and precision. The binary CaGe crystallizes with a CrB-type structure in the orthorhombic space group <i>Cmcm</i> (no. 63; <i>Z</i> = 4; Pearson symbol <i>oC</i>8), where the germanium atoms are interconnected into infinite zigzag chains, formally [Ge]<sup>2−</sup>. The calcium atoms are arranged in monocapped trigonal prisms, centered by Ge atoms. Sr<i><sub>x</sub></i>Ca<sub>1−<i>x</i></sub>Al<sub>2</sub>Ge<sub>2</sub> (<i>x</i> ≈ 0.4) and SrAl<sub>2</sub>Ge<sub>2</sub> have been confirmed to crystallize with a CaAl<sub>2</sub>Si<sub>2</sub>-type structure in the trigonal space group <i>P</i><inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mover accent="true"><mn>3</mn><mo>¯</mo></mover></semantics></math></inline-formula><i>m</i>1 (no. 164; <i>Z</i> = 1; Pearson symbol <i>hP</i>5), where the germanium and aluminum atoms form puckered double-layers, formally [Al<sub>2</sub>Ge<sub>2</sub>]<sup>2−</sup>. The calcium atoms are located between the layers and reside inside distorted octahedra of Ge atoms. All presented structures have a valence electron count satisfying the octet rules (e.g., Ca<sup>2+</sup>Ge<sup>2−</sup> and Ca<sup>2+</sup>[Al<sub>2</sub>Ge<sub>2</sub>]<sup>2−</sup>) and can be regarded as Zintl phases.https://www.mdpi.com/2624-8549/4/4/94crystal structuregermanidesZintl phases |
| spellingShingle | Nian-Tzu Suen Svilen Bobev Structures of Three Alkaline-Earth Metal Germanides Refined from Single-Crystal X-ray Diffraction Data Chemistry crystal structure germanides Zintl phases |
| title | Structures of Three Alkaline-Earth Metal Germanides Refined from Single-Crystal X-ray Diffraction Data |
| title_full | Structures of Three Alkaline-Earth Metal Germanides Refined from Single-Crystal X-ray Diffraction Data |
| title_fullStr | Structures of Three Alkaline-Earth Metal Germanides Refined from Single-Crystal X-ray Diffraction Data |
| title_full_unstemmed | Structures of Three Alkaline-Earth Metal Germanides Refined from Single-Crystal X-ray Diffraction Data |
| title_short | Structures of Three Alkaline-Earth Metal Germanides Refined from Single-Crystal X-ray Diffraction Data |
| title_sort | structures of three alkaline earth metal germanides refined from single crystal x ray diffraction data |
| topic | crystal structure germanides Zintl phases |
| url | https://www.mdpi.com/2624-8549/4/4/94 |
| work_keys_str_mv | AT niantzusuen structuresofthreealkalineearthmetalgermanidesrefinedfromsinglecrystalxraydiffractiondata AT svilenbobev structuresofthreealkalineearthmetalgermanidesrefinedfromsinglecrystalxraydiffractiondata |