For a complex MA₃B₃ possessing a trigonal prismatic geometry, the number of possible isomers are

3

The correct answer is option (1) 3.

For a complex with the formula MA₃B₃ possessing a trigonal prismatic geometry, there are two types of isomers that can be formed:

1. Facial isomers:  In these isomers, three ligands of type A occupy one triangular face of the trigonal prism, while the three ligands of type B occupy the opposite triangular face. There are two possible facial isomers, considering that the ligands can be arranged in two ways on each triangular face.

2. Meridional isomers:  In these isomers, each type of ligand A and B occupies three adjacent positions around the trigonal prism. There are two meridional isomer.

So, in total, there are three isomers for the complex MA₃B₃ with a trigonal prismatic geometry: (1) 3

An example of fac-mer is \(Fe(NH_3)_3Br_3\)