Answer:
Based on the observed isomers of the [CrCl3(NH3)3] complex, it can be ruled out that the complex has a hexagonal planar structure.
Step-by-step explanation:
The fact that only two isomers of the [CrCl3(NH3)3] complex are known to exist is important in ruling out the hexagonal planar structure. If the complex were indeed hexagonal planar, then it would be expected to be symmetric with respect to rotation around the central Cr-N axis. This would result in only one isomer being observed, rather than two.
One of the two known isomers of [CrCl3(NH3)3] is a violet-colored compound that is soluble in water and has a distorted octahedral geometry. The other isomer is a green-colored compound that is insoluble in water and has a distorted tetrahedral geometry. Neither of these isomers matches the expected properties of a hexagonal planar structure.