ELF basin centroids (magenta) for di-cation
Normal modes for neutral triplet
Normal modes for 6-coordinate boron cation
Normal modes for 6-coordinate nitrogen tri-cation
- An ELF basin analysis for this dication based on a b3lyp/6-311g(d,p) calculation has been reported  as revealing five basal carbon to apical carbon basins of 0.75e and a regular disynaptic apical-C-H basin, thus supporting hexacoordination. QTAIM analysis indicated that value of ρ(r) for the bond critical point located for each of the five apical C-C bonds is 0.156 au. The NBO Wiberg bond index at the 6-coordinate carbon is 3.9588, which indicates it is not hypervalent. See also Pentacoordinated_Carbon.
- An obvious question to ask is what happens to this di-cation if two electrons are added to create a neutral species. In fact the lowest unoccupied orbital has degenerate E-symmetry, and so the spin state of such a neutral species would have to be a triplet to preserve symmetry and avoid Jahn-Teller distortion. This species is a higher-order stationary point, with TWO sets of degenerate normal modes (E2, E1) associated with negative force constants. You can inspect this and other modes by right-clicking in the JSmol window on the left and selecting model from the pop-up window that appears (third menu down from top).
- The iso-electronic B1+ and N3+ six-coordinate cations are shown to the left. The first is a stable minimum, but the second has four low frequency imaginary modes indicating it is not a minimum. The neutral iso-electronic Be system is also stable.