Consider octahedral [Co(NH₃)₄(NO₂)(SCN)]⁺…

Cis ligands are $90^\circ$ apart and trans ligands $180^\circ$ apart. Tetrahedral complexes have no geometrical isomers. Octahedral $\text{MA}_3\text{B}_3$ has fac and mer forms. To count the isomers of a monodentate octahedral complex, write the ligands as three trans pairs and count the different sets. The net dipole of two bonds with dipole $\mu$ at an angle $\theta$ is $2\mu\cos(\theta/2)$.