An Orbital Exchange Calculation of Chemical Bonding in Metals
This work calculates the chemical bonds in lithium metal and beryllium metal using the orbital exchange method, a method that recognizes that the two electrons of a bonding pair cannot be completely distinguished when their orbitals overlap to bond. Since in metals there is no preferred bond direction, the symmetry axes of the lattice are chosen as the bonding axes. The calculations sum the primary, secondary and many tertiary bonds along these axes. The bond length and bond energy results are in agreement with the observed values with bond energies accurate to 0.2 eV or better and bond lengths to 0.02Å. The bond lengths are found at the point where the total bond overlap equals 1.0.
These results are compared with the orbital exchange calculations of bonding in diamond, a nonconductor, and graphite, a semiconductor. An uncomplicated explanation for the difference in electrical properties emerges. The conductor, lithium metal, has a 2s bonding orbital which bonds equally in both directions along all axes providing for the continuous flow of electrons. The nonconductor, diamond, has a directional s p hybrid type bonding orbital which bonds in one direction along a single axis, preventing the flow of electrons from atom to atom.