Question

2. Draw an MO diagram for the P3O3 core of the cyclic phosphate P3O9H3 including:
a. A sketch of the LGOs and/or AOs that contribute to the MO ?
b. The symmetry labels of each of the LGOs and/or AOs from part a ?
c. The relative energies of the MOs ?
d. The total bond order of the P3O3 core ?
e. Indicate and explain whether the P3O3 core should be considered aromatic, anti-aromatic, or neither ?

Answer 1

Solution:
a) σ2σ2σ2π4π2;
b) C2v , s px py pz dz2 dx2-y2 dxy dxz dyz;
c) The energy of a s2pz is lower than the energy of bonding p2px or p2py MOs;
d) The total bond order of the P3O3 is 3;
e) Every atom must have a p orbital. Otherwise- nonaromatic