Question

A metal complex with a formula MC$\ell_4$3NH$_3$ is involved in sp$^3$d$^2$ hybridisation. It upon reaction with excess of AgNO$_3$ solution gives ‘x’ moles of AgCl. Consider ‘x’ is equal to the number of lone pairs of electron present in central atom of BrF$_5$. Then the number of geometrical isomers exhibited by the complex is ________

Hint:

When dealing with octahedral complexes, the number of geometrical isomers is determined by how the ligands are arranged. For complexes with three identical ligands and three other different ligands, two possible isomers (fac and mer) exist.

Answer 1

Correct Answer: 2

The complex MC$\ell_4$3NH$_3$ undergoes sp$^3$d$^2$ hybridisation. 
The central atom of BrF$_5$ has 1 lone pair, so x = 1. 
The complex MC$\ell_4$3NH$_3$ has octahedral geometry, leading to 2 possible geometrical isomers: fac and mer. 
Thus, the number of geometrical isomers is 2.