Chapter 5, Problem 5.82MP

(a)

Interpretation Introduction

Interpretation:

The hybridisation of the 8 carbon atoms in the given cyclooctatetraene dianion has to be identified.

Concept introduction:

Hybridization:

• It is the mixing of valence atomic orbitals to get equivalent hybridized orbitals that having similar characteristics and energy.
• Geometry of a molecule can be predicted by knowing its hybridization.
• ${\text{sp}}^{\text{3}}$ hybrid orbitals is produced by hybridization of single s-orbital and three p-orbital.
• ${\text{sp}}^2$ hybrid orbitals is produced by hybridization between one s-orbital and two p-orbitals.
• $\text{sp }$ hybrid orbitals is produced by hybridization of single s-orbital and single p-orbital.

(b)

Interpretation Introduction

Interpretation:

The bonding molecular orbital, anti bonding molecular orbital and the non bonding orbital has to be identified.

Concept introduction:

Molecular orbital theory:

• The atomic orbitals of the atoms constituted in a molecule are combined to produce new orbitals called Molecular Orbitals.
• Like atomic orbitals, a molecular orbital can accommodate maximum two electrons and the two electrons must have opposite spins (Pauli Exclusion Principle).
• The numbers of MO’s are equals to the number of atomic orbitals combined in such a way that the linear combination of similar atomic orbitals to form one bonding and one anti-bonding MO’s.
• The bonding MO’s are lower in energy than the anti-bonding MO’s.
• HOMO is the highest energized occupied orbital in the MO’s.
• Relative energy levels of molecules are according to the energy levels of atomic orbitals.
• LUMO is the lowest energized orbital in the MO’s.

(c)

Interpretation Introduction

Interpretation:

The MO diagram has to be drawn.

Concept introduction:

Molecular orbital theory:

• The atomic orbitals of the atoms constituted in a molecule are combined to produce new orbitals called Molecular Orbitals.
• Like atomic orbitals, a molecular orbital can accommodate maximum two electrons and the two electrons must have opposite spins (Pauli Exclusion Principle).
• The numbers of MO’s are equals to the number of atomic orbitals combined in such a way that the linear combination of similar atomic orbitals to form one bonding and one anti-bonding MO’s.
• The bonding MO’s are lower in energy than the anti-bonding MO’s.
• HOMO is the highest energized occupied orbital in the MO’s.
• Relative energy levels of molecules are according to the energy levels of atomic orbitals.
• LUMO is the lowest energized orbital in the MO’s.

(d)

Interpretation Introduction

Interpretation:

It should be identified whether the dianion is paramagnetic or diamagnetic.

Concept introduction:

Molecular orbital theory:

• The atomic orbitals of the atoms constituted in a molecule are combined to produce new orbitals called Molecular Orbitals.
• Like atomic orbitals, a molecular orbital can accommodate maximum two electrons and the two electrons must have opposite spins (Pauli Exclusion Principle).
• The numbers of MO’s are equals to the number of atomic orbitals combined in such a way that the linear combination of similar atomic orbitals to form one bonding and one anti-bonding MO’s.
• The bonding MO’s are lower in energy than the anti-bonding MO’s.
• HOMO is the highest energized occupied orbital in the MO’s.
• Relative energy levels of molecules are according to the energy levels of atomic orbitals.
• LUMO is the lowest energized orbital in the MO’s.

Paramagnetic property: The presence of unpaired electrons in the electronic configuration of the metal ion in coordination complex.

Diamagnetic property: The absence of unpaired electrons of the metal ion in coordination compound which do repel by the magnet.