The orbitals of some molecules
Posted by RAHMA CAHYANINGRUM pada Maret 6, 2010
The H2 molecule has two valence electrons.
The H2+ molecule has only one valence electron.
The He2 molecule has four valence electrons.
The He2+ molecule has three valence electrons.
Bond order = 1/2 (Σ of electrons in bonding orbitals – Σ of electrons in anti-bonding orbitals).
The bond order in our four examples above are given in the table below.
The bond order must be positive non-zero for a bond to be stable. He2 has a bond order of zero and that is why the He2 molecule is not observed.
http://www.grandinetti.org/Teaching/Chem121/Lectures/MOTheory/index.html by Philip J. Grandinetti