How many geometrical isomers are there for `[Co(NH_(3))_(2) Cl_(4)]^(-)` (octahedral) and `[AuCl_(2) Br_(2)]` (square planar) ?

Explanation

Since `[Co(NH_(3))_(2)CI_(4)]^(Θ)` is `a [Ma_(2)b_(4)]` type octahedral complex ion it has two geometrical isomers which are cis and trans as shown below

(b) Since `[AuCI_(2)Br_(2)]^(Θ)` ion is `[Ma_(2)b_(2)]` type square planar complex ion it has two geometrical isomers viz cis and trans isomers
(c ) `[CuCI_(2)Br_(2)]^(2-)` is tetrahedral and hence has no geometrical isomer .