Why Does a B₁₂H₁₂ Icosahedron Need Two Electrons to be Stable: A First-Principles Electron-Correlated Investigation of B₁₂H_n (n = 6, 12) Clusters

Abstract

In this work, we present large-scale electron-correlated computations on various conformers of B12H12 and B12H6 clusters to understand the reasons behind the high stability of dianion icosahedron (Ih ) and cage-like B12H6 geometries. Although the B12 icosahedron is the basic building block in some structures of bulk boron, it is unstable in its free form. Furthermore, its H-passivated entity, i.e., a B12H12 icosahedron, is also unstable in the free form. However, dianion B12H12 has been predicted to be stable as a perfect icosahedron in the free-standing form. To capture the correct picture for the stability of B12H12 2– and B12H6 clusters, we optimized these structures by employing the coupled-cluster singles and doubles (CCSD) approach and the cc-pVDZ basis set. We also performed the vibrational frequency analysis of the isomers of these clusters using the same level of theory to ensure the stability of the structures. For all of the stable geometries obtained from the vibrational frequency analysis, we additionally computed their optical absorption spectra using the time-dependent density functional theory (TDDFT) approach at the B3LYP/6-31G* level of theory. Our calculated absorption spectra could be probed in future experiments on these clusters.

A Quantum-Chemical Study of Boro-Fullerenes B₆₀H₆₀, B₆₀F₃₀H₃₀ , and B₆₀F₆₀

“…On the other hand, the binding energy that can ensure the stability of a system can be calculated using the following formula [37] = + −…”

Unveiling the electronic and structural consequences of removing two electrons from B12H122−

“…Their only conclusion was that this cage is unstable, and they did not explore any further. 5 It is well-known that the global minimum of B 12 H 12 2− is an icosahedron, 6 so we have used it as a benchmark to validate our genetic algorithms for exploring PESs. During one of the tests, instead of achieving the icosahedron, we obtained a structure with a three-center-two-electron (3c-2e) B-H 2 bond, which was unexpected.…”