For octahedral Mn(II) and tetrahedral Ni(II) complexes,

Question:

For octahedral Mn(II) and tetrahedral Ni(II) complexes, consider the following statements :

(I) both the complexes can be high spin

(II) $\mathrm{Ni}$ (II) complex can very rarely be low spin.

(III) with strong field ligands, $\mathrm{Mn}$ (II) complexes can be low spin.

(IV) aqueous solution of $\mathrm{Mn}$ (II) ions is yellow in color.

The correct statements are :

  1. (I), (III) and (IV) only

  2. (II), (III) and (IV) only

  3. (I), (II) and (III) only

  4. (I) and (II) only


Correct Option: , 3

Solution:

(I) Under weak field ligand, octahedral Mn(II) and tetrahedral Ni(II) both the complexes are high spin complex.

(II) Tetrahedral Ni(II) complex can very rarely be low spin because square planar (under strong ligand) complexes of $\mathrm{Ni}(\mathrm{II})$ are low spin complexes.

(III) With strong field ligands Mn (II) complexes can be low spin because they have less number of unpaired electron (unpaired electron $=1$ )

While with weak field ligands Mn(II) complexes can be high spin because they have more number of unpaired electron (unpaired electron $=5$ )

(IV) Aqueous solution of Mn(II) ions is pink in colour.

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