The bonding of boron atoms has been a subject of interest for scientists for several decades due to its ability to form four or more bonds despite the fact that it is considered to be electron deficient due to the fact that the atom only possesses three valence electrons. A three-center-two-electron bond has been hypothesized to explain the boron atom’s ability to form more than three bonds within a molecule and several papers have been written in support of the existence of this bonding arrangement. This study utilized computational chemistry techniques including the QTAIM method for obtaining the electron densities and Density Functional Theory, the Møller–Plesset Perturbation Theory, the Laplacian scalar, and Poincare-Hopf algebra, specifically, a b3lyp/6-311+g(2d,p) basis set to produce a geometric optimization of C2B5H7. The Trans-Ring configuration of C2B5H7 was reported as the most stable configuration versus a Cis-Ring configuration, an Axial configuration, and an Axial-Equatorial conformation of the carbon atoms within the ring structure. The results showed that the carbon atoms within the molecule each form five bonds, four each to corresponding boron atoms within the ring structure and one bond to its terminal hydrogen atom. The bond lengths reported for the boron atoms were within 0.17 Å of the bond length values for other, simpler molecules with boron atoms bonding to each other and to carbon atoms. The reported boron to boron bond lengths were 0.17 Å longer, which translates to a bond with a smaller amount of energy inside of the bonds. The ring critical point rho values of the Trans-Ring configuration of C2B5H7 were reported as lower than the corresponding bond critical point rho values to which they are attached, all of which indicate that there is not a three-center-two-electron bond present in the molecule.
