Compounds $\mathrm{K}_{2} \mathrm{Ba}\left[\mathrm{Cu}\left(\mathrm{NO}_{2}\right)_{6}\right]$ (A) and $\mathrm{Cs}_{2} \mathrm{Ba}\left[\mathrm{Cu}\left(\mathrm{NO}_{2}\right)_{6}\right]$ (B) exhibit tetragonal elongation and tetragonal compression, respectively. The unpaired electron in A and B are found respectively, in orbitals
(a)$\mathrm{d}_{z^{2}}$ and $\mathrm{d}_{x^{2}-y^{2}}$
(b)$\mathrm{d}_{x^{2}-y^{2}}$ and $\mathrm{d}_{z^{2}}$
(c)$\mathrm{d}_{z^{2}}$ and $\mathrm{d}_{z^{2}}$
(d)$\mathrm{d}_{x^{2}-y^{2}}$ and $\mathrm{d}_{x^{2}-y^{2}}$
Answer
Answer: B ✓ checked by 4AB · confidence high
Explanation
Elongation: unpaired electron in dx²−y²; compression: in dz² (b).