Do Planar Tetracoordinate Fluorine Atoms Exist? Revisiting a Theoretical Prediction

Joonghan Kim; Eunji Park; Jeongmin Park; Jungyoon Kim; Wonil Seo; Dakyeung Oh; Junho Lee; Tae Kyu Kim

doi:10.1021/acs.jpca.3c02021

Do Planar Tetracoordinate Fluorine Atoms Exist? Revisiting a Theoretical Prediction

J Phys Chem A. 2023 Jul 20;127(28):5815-5822. doi: 10.1021/acs.jpca.3c02021. Epub 2023 Jul 11.

Authors

Joonghan Kim¹, Eunji Park¹, Jeongmin Park¹, Jungyoon Kim¹, Wonil Seo¹, Dakyeung Oh¹, Junho Lee², Tae Kyu Kim²

Affiliations

¹ Department of Chemistry, The Catholic University of Korea, Bucheon 14662, Republic of Korea.
² Department of Chemistry, Yonsei University, Seoul 03722, Republic of Korea.

PMID: 37432658
DOI: 10.1021/acs.jpca.3c02021

Abstract

We re-examined the existence of planar tetracoordinate F (ptF) atoms, which was proposed recently by using high-level ab initio methods such as coupled-cluster singles and doubles with perturbative triples (CCSD(T)) with large basis sets. Our calculations indicate that the planar structures of FIn₄⁺ (D_4h), FTl₄⁺ (D_4h), FGaIn₃⁺ (C_2V), FIn₂Tl₂⁺ (D_2h), FIn₃Tl⁺ (C_2V), and FInTl₃⁺ (C_2V) are not the minimum energy states; by contrast, they are transition states. Density functional theory calculations overestimate the size of the cavity formed by the four peripheral atoms, leading to erroneous conclusions regarding the existence of ptF atoms. Our analysis suggests that the preference for non-planar structures in the six cations studied is not due to the pseudo Jahn-Teller effect. Additionally, spin-orbit coupling does not alter the main conclusion that the ptF atom does not exist. If sufficiently large cavity formation by group 13 elements to accommodate the central F^- ion is guaranteed, then the existence of ptF atoms is plausible.