Which of the following statements is incorrect regarding the stereisomerism of the complexes note below (where M statids for a metal, and A, B, C and D are achiral ligands) ?

Options

A. The ocatachedral complex [MABCD(EE)] where EE is a symmetrical bidentate ligand have 12 stereoisomers
B. The facial and meridional isomers of an `MA_(3)B_(3)` octahedral complex are both optically active.
C. The facial and meridional isomer of the octahedral complex `M(A_(3)B_(3))` possess three identical ligands (A or B) at positions 1, 2, 3 and 1, 2, 6 respectively.
D. In the cis and trans isomers of the octahedral complex `(MA_(4)B_(2))` two ligand occupy the posiotion 1, 2 and 1, 6 respectively.

Answer

B

Explanation

Both th efacial and meridional isomers of an octahedral complex, `MA_(3)B_(3)` , are optically inactive as each of these h as a plane of symmetry:

In an octahedral complex 1,2 positions are cis positions as they have `90^(@)` separation While 1, 6 positions are trans positions as they have a `180^(@)` separation.