Question

Complexes $\left[M{L}_5\right]$ of metals Ni and Fe have ideal square pyramidal and trigonal bipyramidal and geometries, respectively. The sum of the ${90}^0,{120}^0$ and ${180}^{0}L-M-L$ angles in the two complexes is

Answer 1

For trigonal bipyramidal geometry
Total number of ${180}^{0}L-M-L$ bond angles = 1
Total number of ${90}^{0}L-M-L$ bond angles = 6
Total number of ${120}^{0}L-M-L$ bond angles = 3
Total = 10

For square pyramidal geometry
Total number of ${180}^{0}L-M-L$ bond angles = 2
Total number of ${90}^{0}L-M-L$ bond angles = 8
Total number of ${120}^{0}L-M-L$ bond angles = 0
Total = 10
Total for both the structures = 20