Question

The number of complexes from the following with no electrons in the t$_{2g}$ orbital is _______.
TiCl$_4$, [MnO$_4$]$^{-}$, [FeO$_4$]$^{2-}$, [FeCl$_4$]$^{-}$, [CoCl$_4$]$^{2-}$

• A. 3
• B. 1
• C. 4
• D. 2

Answer 1

Answer: (A)

3

Answer 2

To determine the number of complexes with no electrons in the $t_2$ orbital, analyze each complex and its oxidation state, electronic configuration, and crystal field splitting.
Step 1: Analyze each complex
1.$\text{TiCl}_4$:
- Oxidation state of Ti: $+4 \, (\text{Ti}^{4+})$.
- Electronic configuration of $\text{Ti}^{4+}$: $3d^0$.
- No electrons in $t_2$ orbitals.

2.$[\text{MnO}_4]^-$:
- Oxidation state of Mn: $+7 \, (\text{Mn}^{7+})$.
- Electronic configuration of $\text{Mn}^{7+}$: $3d^0$.
- No electrons in $t_2$ orbitals.

3.$[\text{FeO}_4]^{2-}$:
- Oxidation state of Fe: $+6 \, (\text{Fe}^{6+})$.
- Electronic configuration of $\text{Fe}^{6+}$: $3d^0$.
- No electrons in $t_2$ orbitals.
4.$[\text{FeCl}_4]^-$:
- Oxidation state of Fe: $+2 \, (\text{Fe}^{2+})$.
- Electronic configuration of $\text{Fe}^{2+}$: $3d^6$.
- $t_2$ orbitals are populated with electrons ($t_2^3e^3$).
5.$[\text{CoCl}_4]^{2-}$:
- Oxidation state of Co: $+2 \, (\text{Co}^{2+})$.
- Electronic configuration of $\text{Co}^{2+}$: $3d^7$.
- $t_2$ orbitals are populated with electrons ($t_2^4e^3$).
Step 2: Count complexes with no $t_2$ electrons
- $\text{TiCl}_4$, $[\text{MnO}_4]^-$, and $[\text{FeO}_4]^{2-}$ have no electrons in $t_2$ orbitals.
- $[\text{FeCl}_4]^-$ and $[\text{CoCl}_4]^{2-}$ have electrons in $t_2$ orbitals.
Conclusion:
The number of complexes with no electrons in the $t_2$ orbital is:
$3 \, (\text{TiCl}_4, \, [\text{MnO}_4]^-, \, [\text{FeO}_4]^{2-}).$
Final Answer: (1).