Molecule with a three electron bond is :

Molecules with odd electron bond are

In benzene molecule there are three pi bonds and

The distribution of electrons among molecular orbitals is called the electronic configuration of the molecule which provides us the following very important informations about the molecule. (A)Stability of molecule : The molecule is stable if number of bonding moleculer orbital electrons (N_b) is greater than the number of antibonding molecular orbital electrons (N_a) . (B) Bond order : Bond order =1/2(N_b-N_a) A positive bond order means a stable molecule while a negative or zero bond order means an unstable molecule. ( C)Nature of the bond : Bond order 1,2 and 3 corresponds to single , double and triple bonds respectively. (D)Bond length: Bond length decreases as bond order increases. (E)Magnetic nature: Molecular orbitals in a molecule are doubly occupied , the substance is diamagnetic and if one or more molecular orbitals are singly occupied, it is paramagnetic. Which of the following statements is incorrect ?

The number of three centre two electron bonds in a molecule of diborane is________.

The number of three centre two electron bonds in a molecule of diborane is________.