The Si, Ge and Sn analogues of ethene have a special bond between the E atoms. As we found in ab initio calculations, the polarized banana bond (called papaw bond) in the trans-bent equilibrium geometry of these compounds have a bond order smaller than two but larger than one: BSiSi1.76, BGeGe1.61 and BSnSn1.46. The d orbitals of the E atoms do not participate in the EE bond. The bond order is smaller than that characteristics for a σ + π double bonds as the pz orbital of one E atom interacts with the s orbital of the other one and only to a lesser extent with its pz orbitals. The trans-bent equilibrium structure corresponds to a valence state between sp3 and sp2 and to valences VSi3.78, VGe3.59 and VSn 3.40. The ab initio bond orders are in reasonable agreement with the bond numbers calculated from the formula of Pauling supporting the applicability of the latter relation.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry