Structural Diagram of [Co($NH_{3}$)_{5}Cl]^{2+} — Werner's Inner and Outer Sphere:

Labelled Components of a General Coordination Compound [Co($NH_{3}$)_{5}Cl]$Cl_{2}$:

[Co($NH_{3}$)_{5}Cl]$Cl_{2}$
  └─── Coordination entity (inner sphere): [Co($NH_{3}$)_{5}Cl]^{2+}
         ├── Central metal ion: $Co^{3+}$ (oxidation state = primary valence = +3)
         ├── Ligands in sphere: 5 × $NH_{3}$ (neutral, monodentate) + 1 × $Cl^{-}$ (anionic, monodentate)
         ├── Coordination number: 6 (total donor atoms bonded to Co)
         └── Secondary valence: 6 (non-ionisable, directional)
  └─── Counter ions (outer sphere): 2 × $Cl^{-}$ (ionisable in solution)
         └── Primary valence contribution: +3 = charge of inner sphere ion

Square Planar Geometry — cisplatin (cis-[Pt($NH_{3}$)_{2}$Cl_{2}$]):

Labels:

• $Pt^{2+}$ at centre ($d^{8}$ configuration → square planar)
• Two $NH_{3}$ ligands on the same side (cis position)
• Two $Cl^{-}$ ligands on the same side (cis position)
• Clinically active as anticancer drug; trans isomer (transplatin) is clinically inactive