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Grade 12th passPhysical Chemistry

Which of the following diatomic molecular species only pi bonds according to M.O.T?
A)O2
B)N2
C)C2
D)Be2

Profile image of SAMBHU MANDAL
7 Years agoGrade 12th pass
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1 Answer

Profile image of Arun
7 Years ago
sigma 2px if filled will be strongly repelled by the electron density of already filled sigma 2s orbitals (both electron densities lie at inter nuclear axis). Due to this, the energy of sigma 2px is surprisingly found higher than pi 2py and pi 2pz energy.
Therefore, while filling, the electrons occupy pi 2py and pi 2pz orbitals instead of normal sigma 2px (that remains vacant).
Presence of these 4 electrons in pi 2py and pi 2pz orbitals result in formation of two pi bonds.