Question

Complexes [ML₅] of metals $\mathrm{Ni}$ and $\mathrm{Fe}$ have ideal square pyramidal and trigonal bipyramidal geometries, respectively. The sum of the$90°$, $120°$and $180°$ L-M-L angles in the two complexes is

Answer 1

Step 1:

For trigonal bipyramidal geometry

Total number of $180°$ L-M-L bond angles = $1$

Total number of $90°$ L-M-L bond angles = $6$

Total number of $120°$ L-M-L bond angles = $3$

Total = $10$

Step 2:

For square pyramidal geometry

Total number of $180°$L-M-L bond angles = $2$

Total number of $90°$ L-M-L bond angles = $8$

Total number of $120°$ L-M-L bond angles = $0$

Total = $10$

Hence, the total for both the trigonal bipyramidal geometry and square pyramidal geometry =$20$