On the structure of heptalithium distannide: Li<sub>7</sub>Sn<sub>2</sub> or Li<sub>7−<i>x</i></sub>Sn<sub>2</sub> (0.3 < <i>x</i> < 0.5)
Li-Sn intermetallics are promising candidates for high-capacity Li-ion battery anodes, yet, the precise crystal structures of some "known" binary phases remain unresolved. One such phase, Li<sub>7</sub>Sn<sub>2</sub>, originally reported in 1975, is re-examined here using single-crystal X-ray diffraction methods. Its orthorhombic structure (space group <i>Cmmm</i>, no. 65) features isolated Sn atoms and Sn-Sn dumbbells in a matrix of Li atoms. The present study indicates occupational disorder on one of the Li sites in Li<sub>7</sub>Sn<sub>2</sub>, meaning that it is a non-stoichiometric phase with revised composition of Li<sub>7-<i>x</i></sub>Sn<sub>2</sub> (0.3 < <i>x</i> < 0.5). In the most extreme case, when the Li atomic site in question is completely empty, the composition becomes Li<sub>6.5</sub>Sn<sub>2</sub> or Li<sub>13</sub>Sn<sub>4</sub>. Analysis of the chemical bonding through electronic structure calculations indicates significant covalency of Sn-Sn and Li-Sn interactions.
Authors
- Kowsik Ghosh (ORCID: https://orcid.org/0000-0003-2622-7046)
- Alexander Ovchinnikov (ORCID: https://orcid.org/0000-0002-0537-4234)
- A. Nandakumar (ORCID: https://orcid.org/0009-0002-4285-3960)
- Candace K. Chan (ORCID: https://orcid.org/0000-0003-4329-4865)
- Svilen Bobev (ORCID: https://orcid.org/0000-0002-0780-4787)
- Salina Rahman (ORCID: https://orcid.org/0000-0002-0851-4124)
Institutions
- Arizona State University (US)
- Technische Universität Dresden (DE)
- University of Delaware (US)
Publication Details
- Journal
- Dalton Transactions
- Published
- 2025-01-01
- DOI
- https://doi.org/10.1039/d5dt01022e
- Primary Topic
- Inorganic Chemistry and Materials
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- National Science Foundation
- Arizona State University
- Eyring Materials Center, Arizona State University
- Division of Materials Research
- Division of Electrical, Communications and Cyber Systems