Question

Which of the following configuration can undergo distortion ?

• A. $t_{2g}\,^{6}e^{1}_{g}$
• B. $t_{2g}\,^{6}e^{2}_{g}$
• C. $t_{2g}\,^{6}e^{4}_{g}$
• D. $t_{2g}\,^{6}e^{0}_{g}$

Answer 1

Answer: (A)

$t_{2g}\,^{6}e^{1}_{g}$

Answer 2

According to Jahn-Teller theorem, any non-linear molecular system in a degenerate electronic state is unstable and readily undergoes distortion to give a system of lower symmetry and lower energy by removing the degeneracy. This effect is more important for odd number occupancy of the eg. level. Thus, $t_{2g}^{6} e_{g}^{1}$ readily undergoes distortion