Density functional calculations of hypothetical neutral hollow octahedral molecules with a 48-atom framework: Hydrides and oxides of boron, carbon, nitrogen, aluminum, and silicon

We computed via first-principles density functional theory calculations (employing both the local density and generalized gradient approximations) the dimensions, bond lengths and angles, binding energy, and HOMO–LUMO gap of the following hypothetical neutral hollow octahedral molecules: B48H24, C48H48, C96H80 (formed by bonding two C48H48 molecules), N48H24, Al48H24, and Si48H48; B24O24, C24O24, N24O24, Al24O24, and Si24O24. Each molecule consists of a large hollow framework of six puckered eight-membered rings whose planes are either mutually perpendicular or parallel, so that each molecule possesses only eight- and nine-membered rings. The hydrides have their hydrogen atoms attached only to the two-atom bridging sites on the framework. The oxides have their oxygen atoms occupying exclusively the two-atom bridging sites of the framework alternating with the (B, C, N, Al, Si) atoms exclusively occupying the three-atom bridging sites. We also calculated the infrared spectra of the C48H48 and the C24O24 mo...