Question

Atomic number of Mn. Fe and Co are 25, 26 and 27 respectively. Which of the following inner orbital octahedral complex ions are diamagnetic ?
A. `[Co(NH_(3))_(6)]^(3+)`
B. `[Mn(CN)_(6)]^(3-)`
C. `[Fe(CN)_(6)]^(4-)`
D. `[Fe(CN)_(6)]^(3-)`

Answer 1

Correct Answer - A::C

Number of unpaired electron `= 1`
Magnetic property = Paramagnetic
Thus, `[Co(NH_(3))_(6)]^(3+)` and `[Fe(CN)_(6)]^(4-)` are diamagnetic.
Hence, correct choices are options (a) and (c).