For which transition metal ions are low spin complexes possible:

Options

A. (a) `Rh^(3+)`
B. (b) `Mn^(3+)`
C. (c) `Ru^(2+)`
D. (d) All are correct

Answer

D

Explanation

`._(44)Ru=4d^(7) 5s^(1)overset(After pairi ng)rarr4d^(8)5s^0`
`._(45)Rh=4d^(8)5s^(1) overset(After pairi ng)rarr4d^(9)5s^0`
`._(25)Mn=3d^(5)4s^2overset(After pairi ng)rarr3d^(7)4s^0`
Due to strong ligand pairing occurs and all have vacant 'd' orbital, thus, it can from low spin complex.
It is present in low oxidation state, so, it forms low spin complex.