The one that is not expected to show isomerism is :

Simplified absorption spectra of three complexes ((i), (ii) and (iii)) of Mn⁺ ion are provided below; their $$\lambda $$_max values are marked as A, B and C respectively. The correct match between the complexes and their $$\lambda $$_max values is
(i) [M(NCS)₆]^{(–6 + n)}
(ii) [MF₆]^{(–6 + n)}
(iii) [M(NH₃)₆]ⁿ⁺

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

(I) both the complexes can be high spin.
(II) Ni(II) complex can very rarely be low spin.
(III) with strong field ligands, Mn(II) complexes can be low spin.
(IV)aqueous solution of Mn(II) ions is yellow in colour.

The correct statements are :

Consider that a d⁶ metal ion (M²⁺) forms a complex with aqua ligands, and the spin only magnetic moment of the complex is 4.90 BM. The geometry and the crystal field stabilization energy of the complex is