Which ions exhibit sp mixing
B2 OR (C2)2- OR O2+ OR BOTH B2 & (C2)2-

It is sp mixing and not sp hybridization
you know that Li2 , Be2, B2, C2, N2 follow a different sequence for in which sigma 2pz is higher in energy then pi 2px and pi 2py
this is due to proximity of 2s orbital with 2p orbitals in the system of less than 14 electrons.
Hence both B2 and C2 2- can show sp mixing.

Maam please explain this one in class