Molecular Orbitals of Nitric Oxide

This "molecular orbital diagram" in this exercise is a bit different from those of other exercises and, strictly speaking, is not really a molecular orbital diagram. The orbital energies for nitric oxide derive from ab initio calculations.

Before examining this diagram, careful examine the molecular orbitals for carbon monoxide. Nitric oxide differs from carbon monoxide in that it has an unpaired electron. In this particular case, the presence of a single electron in an orbital destroys the symmetry of the molecule and the usual degeneracy for the pi bonding orbitals and pi antibonding orbitals is destroyed.

Draw the Lewis structure for nitric oxide and use it to answer the following questions.

  1. What is the predicted NO bond order?
  2. On which atom is the unpair electron located?
  3. Does adding an electron to form NO- strengthen or weaken the bond?
  4. Does removing an electron to form NO+ strengthen or weaken the bond?

Answer these same questions using the molecular orbital diagram.

Molecular Orbital Diagram of CO
View Along

HF     N2     F2     CO     NO     H2O     CO2

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© Copyright 2001, David N. Blauch