Answer to Question #142416 in Inorganic Chemistry for PRAJAKTA

Question

The value of splitting energy (Delta-o) in an Octahedral complex of Mn(III) is 15,800 cm-1 and the pairing energy (P) is 28,000 cm-1.
i) Will the complex be a high spin or low spin type?
ii) Which of the spin state for this complex will show greater Jahn-Teller distortion and why? Draw the splitting diagram of high-spin and low-spin cases and explain

Answer 1

i) Will the complex be a high spin or low spin type?

the complex is High spin because pairing energy is greater then splitting energy

ii) Which of the spin state for this complex will show greater Jahn-Teller distortion and why? Draw the splitting diagram of high-spin and low-spin cases and explain

d¹, d², low spin d⁴, low spin d⁵, low spin d⁷, and d9⁹, would be expected to exhibit Jhan-Teller distortion.

Elongation

Elongation Jahn-Teller distortions occur when the degeneracy is broken by the stabilization (lowering in energy) of the d orbitals with a z component, while the orbitals without a z component are destabilized (higher in energy)

is due to the dxy and dx2−y2

dx2−y2 orbitals having greater overlap with the ligand orbitals, resulting in the orbitals being higher in energy. Since the dx2−y2

dx2−y2 orbital is antibonding, it is expected to increase in energy due to elongation. The dxy

dxy orbital is still nonbonding, but is destabilized due to the interactions. Jahn-Teller elongations are well-documented for copper(II) octahedral compounds

Compression Jahn-Teller distortions occur when the degeneracy is broken by the stabilization (lowering in energy) of the d orbitals without a z component, while the orbitals with a z component are destabilized (higher in energy)