Question
The crystal field splitting energy of [ Co ( oxalate )_ 3 ]^ 3- complex is ' n ^ times that of the [ Cr ( oxalate )_ 3 ]^ 3- complex. Here ' n ^ is \_\_\_\_. (Assume _ 0 P )
JEE Main
Chemistry
Coordination Compounds
2026
JEE Main 2026 (23 January Shift 1)
JEE Main Chemistry Question (2026) — Solution
Options
- A. A
- B. B
- C. C
- D. D
Answer
A. A
Step-by-step solution
The Crystal Field Stabilization Energy (CFSE) is calculated based on the electronic configuration of the central metal ion in the octahedral field. For [Co(ox)_3]^ 3- : Cobalt is in +3 oxidation state. Co^ 3+ has a d^6 configuration. Given _0 P, it is a low spin complex. The electrons fill the t_ 2g level first. Configuration: t_ 2g ^6 e_g^0. CFSE for Co^ 3+ = 6 (-0.4 _0) + 0 (0.6 _0) = -2.4 _0. For [Cr(ox)_3]^ 3- : Chromium is in +3 oxidation state. Cr^ 3+ has a d^3 configuration. Configuration: t_ 2g ^3 e_g^0. CFSE for Cr^ 3+ = 3 (-0.4 _0) + 0 (0.6 _0) = -1.2 _0. Comparing the magnitudes of the stabilization energies: Magnitude of CFSE for Co^ 3+ = 2.4 _0. Magnitude of CFSE for Cr^ 3+ = 1.2 _0. The ratio n = 2.4 _0 1.2 _0 = 2.
Related: Chemistry — Coordination Compounds · All PYQ Banks