1. Mononuclear metal carbonyls contain only one metal atom as the central atom . 2. None of the triangles of coordinating atoms and the central atom are coplanar. 3. The central atom or ion, together with all ligands comprise the coordination sphere. 4. The central atoms or ion and the donor atoms comprise the first coordination sphere. 5. The central atom in these endohedral complexes is located in the center of the cage. 6. Therefore, the central atom is predicted to adopt a " linear " geometry. 7. The molecule has a distance between sulfur atoms of and angle at the central atom of. 8. The triangles of coordinating atoms and the central atom have two coplanar, and one perpendicular. 9. The number of donor atoms attached to the central atom or ion is called the coordination number. 10. The " A " represents the central atom and always has an implied subscript one.
