Search for lowest-energy structure of Zintl dianion Si12 2-, Ge12 2-, and Sn12 2-

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

17 Scopus Citations
View graph of relations



Original languageEnglish
Article number154326
Journal / PublicationJournal of Chemical Physics
Issue number15
Publication statusPublished - 2008
Externally publishedYes


We perform an unbiased search for the lowest-energy structures of Zintl dianions (Si12 2-, Ge12 2-, and Sn12 2-), by using the basin-hopping (BH) global optimization method combined with density functional theory geometric optimization. High-level ab initio calculation at the coupled-cluster level is used to determine relative stabilities and energy ranking among competitive low-lying isomers of the dianions obtained from the BH search. For Si12 2-, all BH searches (based on independent initial structures) lead to the same lowest-energy structure Si 12a 2-, a tricapped trigonal prism (TTP) with Cs group symmetry. Coupled-cluster calculation, however, suggests that another TTP isomer of Si 12c 2- is nearly isoenergetic with Si 12a 2-. For Sn12 2-, all BH searches lead to the icosahedral structure Ih - Sn 12a 2-, i.e., the stannaspherene. For Ge12 2-, however, most BH searches lead to the TTP-containing Ge 12b 2-, while a few BH searches lead to the empty-cage icosahedral structure Ih - Ge 12a 2- (named as germaniaspherene). High-level ab initio calculation indicates that Ih - Ge 12a 2- and TTP-containing Ge 12b 2- are almost isoenergetic and, thus, both may be considered as candidates for the lowest-energy structure at 0 K. Ge 12a 2- has a much larger energy gap (2.04 eV) between highest occupied molecular orbital and lowest unoccupied molecular orbital than Ge 12b 2- (1.29 eV), while Ge 12b 2- has a lower free energy than Ih - Ge 12a 2- at elevated temperature (>980 K). The TTP-containing Si 12a 2- and Ge 12b 2- exhibit large negative nuclear independent chemical shift (NICS) value (∼-44) at the center of TTP, indicating aromatic character. In contrast, germaniaspherene Ih - Ge 12a 2- and stannaspherene Ih - Sn 12a 2- exhibit modest positive NICS values, ∼12 and 3, respectively, at the center of the empty cage, indicating weakly antiaromatic character. © 2008 American Institute of Physics.

Bibliographic Note

Publication details (e.g. title, author(s), publication statuses and dates) are captured on an “AS IS” and “AS AVAILABLE” basis at the time of record harvesting from the data source. Suggestions for further amendments or supplementary information can be sent to