Question

The type of d-d transition of the electron occurs in $[Ti(H_2O)_6]^{3+}$ is:

• A. $t_{2g}^2 e_g^1 \rightarrow t_{2g}^3 e_g^0$
• B. $t_{2g}^1 e_g^2 \rightarrow t_{2g}^2 e_g^1$
• C. $t_{2g}^1 e_g^3 \rightarrow t_{2g}^2 e_g^2$
• D. $t_{2g}^1 e_g^2 \rightarrow t_{2g}^2 e_g^0$
• E. $t_{2g}^2 e_g^1 \rightarrow t_{2g}^3 e_g^1$

Hint:

In octahedral fields, the $t_{2g}$ orbitals are lower in energy than the $e_g$ orbitals, and electron transitions occur between these orbitals.

Answer 1

The Correct Option is C

In $[Ti(H_2O)_6]^{3+}$, titanium has an oxidation state of +3, which means it has 3 electrons in the 3d orbital. The electron configuration follows the crystal field splitting of the $d$-orbitals into two sets: $t_{2g}$ and $e_g$. 
The electron transition observed in the octahedral field corresponds to $t_{2g}^1 e_g^3 \rightarrow t_{2g}^2 e_g^2$.