A coordination complex has only two stereo isomers, having octahedral coordination geometry. Identify the complex(es) among the following:
`[Cr(H_(2)O_5 Cl]Cl_(2)]Cl_(2),[Cr(H_2O)_(3)Cl_(3)],[Ni(NH_3)_(4)Cl_(2)],[NH_4]_(2)[NiCl_6]`

Options

A. only `[Cr(H_2O)_(5)Cl]Cl_(2)`
B. `[Cr(H_2O)_(3)Cl_3] and [NH_4]_(4)[NiCl_(6)]`
C. `[Cr(H_2O)_(3)Cl_3] and [Ni(NH_3)_(4)Cl_(2)]`
D. only `[Ni(NH_3)_(4)Cl_(2)]`

Answer

C

Explanation

`[Cr(H_2O)_(5)Cl]Cl_2` two structural isomers

`[Cr(H_2O)_(3)Cl_3]` Fac and Mer isomers
`[Ni(NH_3)_(4)Cl_2]` Cis and Trans isomers
`(NH_4)_(2)[NiCl_6]` No isomer.