Re: What is the structure of NO2+ ligand? Which are the donated electrons?

In the Lewis structure system, NO2+ would have sixteen valence electrons 
with nitrogen as the central atom.  Each oxygen atom would be doubly 
bonded to the nitrogen and nitrogen would bear the +1 formal charge. The 
molecule would be predicted to be linear. Nitrogen would have no lone 
pairs, so it could not be the donor site when NO2+ is a ligand.  It would 
seem that one of the oxygen atoms with their lone pairs would be the 
donor. 

I am not sure what molecular orbital theory would predict, but it looks 
like there is a "non bonding type" of orbital which is composed of oxygen 
orbitals.  That would fit with the Lewis prediction.