Question

A. Prepare a molecular orbital energy level diagram for a CuCl+ ion. Use sketches to show clearly how the atomic orbitals interact to give MOs.

B. What is the bond order for the ion and how many unpaired electrons does the molecule have?

C. Which molecular orbital of the ion would you predict to interact with Clto form the CuCl2 molecule?

Answer 1

Coordination compounds (or complexes) are molecules and extended solids that contain bonds between a transition metalion and one or more ligands. In forming these coordinate covalent bonds, the metal ions act as Lewis acids and the ligands act as Lewis bases. Typically, the ligand has a lone pair of electrons, and the bond is formed by overlap of the molecular orbital containing this electron pair with the d-orbitals of the metal ion. Ligands that are commonly found in coordination complexes are neutral molecules (H₂O, NH₃, organic bases such as pyridine, CO, NO, H₂, ethylene, and phosphines PR₃) and anions (halides, CN^-, SCN^-, cyclopentadienide (C₅H₅^-), H^-, etc.). The resulting complexes can be cationic (e.g., [Cu(NH₃)₄]²⁺), neutral ([Pt(NH₃)₂Cl₂]) or anionic ([Fe(CN)₆]^4-). As we will see below, ligands that have weak or negligible strength as Br