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Updated: May 18, 2026

Negative Additive Manufacturing of Complex Shaped Boron Carbides
Published on: September 18, 2018
Many M©B(n) boron wheels are local, but not global minima
Yunlong Liao1, Clara Leticia Cruz, Paul von Ragué Schleyer
1Department of Chemistry, Institute for Functional Nanomaterials, University of Puerto Rico, Rio Piedras Campus, San Juan, Puerto Rico 00931.
Abstract:
Twenty-six planar boron wheels with a central hypercoordinate atom (M©B(n), M is a 2nd or 3rd period element) were designed following the Schleyer-Boldyrev concept of geometric and electronic fit whereby in-plane σ- as well as π-aromaticity contribute to the chemical bonding. Global minimum searches using an efficient newly implemented method reveal that most of these boron wheels are only local, rather than global minima. However, the Be©B(8) triplet planar wheel global minimum is a new member of the planar hypercoordinate M©B(n) family. Six categories classify the structures of the other global minima: planar wheels, planar non-wheel forms, quasi-two-center-wheels, as well as leaf-like, pyramid-like, and umbrella-like geometries.
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