The number of complexes from the following with no electrons in the \(\mathrm{t}_{2}\) orbital is ____. \(\mathrm{TiCl}_{4},\left[\mathrm{MnO}_{4}\right]^{-},\left[\mathrm{FeO}_{4}\right]^{2-},\left[\mathrm{FeCl}_{4}\right]^{-},\left[\mathrm{CoCl}_{4}\right]^{2-}\)

JEE Main · 2024 · 05 Apr 2024 · Shift 2 · Coordination Compounds

The number of complexes from the following with no electrons in the

t_{2}

orbital is ____.

TiCl_{4}, [MnO_{4}]^{-}, [FeO_{4}]^{2 -}, [FeCl_{4}]^{-}, [CoCl_{4}]^{2 -}

Answer: (A)

T i C l_{4}

T i^{4 +}

3 d^{0}

—

e^{0} t_{2}^{0}

, no

t_{2}

electrons.

[M n O_{4}]^{-}

M n^{7 +}

3 d^{0}

—

e^{0} t_{2}^{0}

, no

t_{2}

electrons.

[F e O_{4}]^{2 -}

F e^{6 +}

3 d^{2}

; filling the (lower) tetrahedral

e

level first, this is

e^{2} t_{2}^{0}

— no

t_{2}

electrons.

[F e C l_{4}]^{-}

: Fe here is

F e^{3 +}

(

3 d^{5}

), which in a high-spin tetrahedral field fills as

e^{2} t_{2}^{3}

— has electrons in

t_{2}

[C o C l_{4}]^{2 -}

C o^{2 +}

3 d^{7}

, filling as

e^{4} t_{2}^{3}

— has electrons in

t_{2}

.
Three complexes —

T i C l_{4}

[M n O_{4}]^{-}

[F e O_{4}]^{2 -}

— have no electrons in the

t_{2}

orbital.

JEE Main · 2024 · 05 Apr 2024 · Shift 2 · Single correct option