The Boron Buckyball has an Unexpected Th Symmetry

TL;DR

This study reveals that the boron buckyball adopts a Th symmetry with a puckered cage structure, differing from the expected icosahedral symmetry, and exhibits a larger HOMO-LUMO gap than previously reported.

Contribution

It demonstrates that the boron buckyball's true energy minimum has Th symmetry, not Ih, and provides detailed electronic structure analysis at the B3LYP/6-31G(d) level.

Findings

Boron buckyball favors Th symmetry over Ih.

HOMO-LUMO gap is 1.94 eV, twice previous estimates.

Valence orbital structure matches that of carbon analogue.

Abstract

The boron buckyball avoids the high symmetry icosahedral cage structure. The previously reported Ih symmetric structure is not an energy minimum in the potential energy surface and exhibits a spontaneous symmetry breaking to yield a puckered cage with a rare Th symmetry. The HOMO-LUMO gap is twice as large as the reported value and amounts to 1.94 eV at B3LYP/6-31G(d) level. The valence orbital structure of boron buckyball is identical to the one in the carbon analogue.