The tetrahedral complex [CoCl4]^2- is high spin. Using CFSE_tet=(-0.6 n_e+0.4 n_t_2)Delta_t, ignoring pairing energy, and Delta_t=tfrac49Delta_o, calculate its CFSE expressed in units of Delta_o (two decimals).

JEE Advanced levelNumerical answerDifficulty 3 of 3cc054

The tetrahedral complex $[CoCl X_{4}] X^{2 -}$ is high spin. Using CFSE $_{t e t} = (- 0.6 n_{e} + 0.4 n_{t_{2}}) Δ_{t}$ , ignoring pairing energy, and $Δ_{t} = \frac{4}{9} Δ_{o}$ , calculate its CFSE expressed in units of $Δ_{o}$ (two decimals).

Numerical answer type, answer in Delta_o, tolerance 0.01.

Co(II) is

d^{7}

, and tetrahedral high spin

d^{7}

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

. CFSE

= - 0.6 \times 4 + 0.4 \times 3 = - 1.2 Δ_{t}

. Converting,

- 1.2 \times \frac{4}{9} = - 0.533 Δ_{o}

, i.e.

- 0.53 Δ_{o}