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

Abstract

The notion that a regular icosahedron is unattainable in neutral B₁₂H₁₂ has persisted for nearly 70 years. This is because 24 valence electrons are used for B–H bonds, while another 24 electrons are necessary to maintain the deltahedron, unlike the 26 used in the dianion. According to Wade–Mingos rules, the neutral system should be a deltahedron with a capped face. Nevertheless, our exploration of the potential energy surface of B₁₂H₁₂ reveals that the global minimum is a closed-shell form with an H₂ unit attached to a boron vertex of B₁₂H₁₀, preserving the deltahedral boron skeleton.