Multiple choice

Which of the following d-electronic configurations will give maximum CFSE in an octahedral complex?

  1. Low spin-d4

  2. High spin-d4

  3. Low spin-d5

  4. High spin-d5

  5. High spin-d7

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In octahedral complexes, CFSE is given by the formula:  CFSE = value of t2g (n) + value of eg (n) Dq, Now, CFSE for low-spin d4 = -4 (4) + 6 (0) = -16 + 0 = -16 Dq CFSE for high-spin d4 = -4 (3) + 6 (1) = -12 + 6 = -6 Dq CFSE for low-spin d5 = -4 (5) + 6 (0) = -20 + 0 = -20 Dq CFSE for high-spin d5 = -4 (3) + 6 (2) = -12 + 12 = 0 Dq CFSE for low-spin d7 = -4 (5) + 6 (2) = -20 + 12 = -8 Dq Hence, low-spin d5 will give maximum CFSE in an octahedral complex.