Electronic structure, stability, and oxidation of boron-magnesium clusters and cluster solids

Abstract

Electronic structure studies on MgmBn (-) (1 ≤ n ≤ 15, 0 ≤ m ≤ 3) clusters have been performed to identify the nature of bonding and the origin of stability in the mixed clusters. Boron clusters are found to have planar structures marked by tangential, radial, and π aromaticity. The maximum stability is achieved for when all three types of aromaticity are quenched. The ring like Bn (-) clusters are shown to be electron deficient for n = 6-8, and the addition of Mg atoms is found to enhance the stability of the boron cluster through ionic bonding that quenches the aromaticity and produces umbrella-like structures. Several species including MgB6 (-), MgB8 (-), Mg2B(-), and Mg3B7 (-) are found to have the largest Mg binding energies due to this mechanism. The transfer of a single electron from the Mg atom to the boron cluster results in a Mg atom with a half-filled 3s orbital that may serve as an ignition center for combustion. Studies on the MgB7 and MgB4 cluster solids indicate that they are constructed from icosahedral and umbrella-like motifs and are semiconductors with band gap energies of 1.46 eV and 0.41 eV, respectively.

Geometry and bonding of small binary boron-aluminum clusters BnAln (n = 1–7): Electron donation and interlocking aromaticity

“…These results agree with previous report on stabilization of B 7 cycle which becomes the most stable form at triply negative charge [50].…”

Electronic Structure and Thermochemical Parameters of the Silicon-Doped Boron Clusters BnSi, with n = 8–14, and Their Anions

“…12 The systematic investigations on small and singly doped B n M clusters with n up to 12, where M are transition metals or metals such as Sc, Zr, Al, have been studied theoretically 13−15 and experimentally. 16−20 The nature of bonding and origin of stability in the doubly metal doped boron clusters B n M 2 (M = Co, Fe) 21 and the electronic structure of mixed clusters, such as the Mg n B m clusters (1 ≤ n ≤ 15, 0 ≤ m ≤ 3) in which boron plays the role of dopant, 22 were analyzed in details.…”

Dynamic Mg2B8 Cluster: A Nanoscale Compass

“…To locate the global minimum (GM) of Mg 2 B 8 , we performed global searches using the Coalescence Kick (CK) algorithm . Our choice of the present system benefits from two prior computational studies on relevant binary clusters, although dynamic fluxionality is either not recognized or not possible in those systems . For the Mg 2 B 8 cluster in this work, a total of 3000 stationary points were probed on the potential energy surface in the CK global searches.…”