Answer: Donates electron density from filled d orbitals back into the CO pi* orbital (backbonding), strengthening M-C and weakening C-O.
- A Donates electron density from filled d orbitals back into the CO pi* orbital (backbonding), strengthening M-C and weakening C-O
- B Instead generally accepts additional pi electron density directly back from the filled CO pi orbital in routine practice overall
- C Transfers most of its electrons to the CO ligand mainly through an ionic electron-transfer mechanism in most cases under typical conditions
- D Forms highly no pi-type interaction with CO, relying mainly on simple sigma bonding according to standard textbooks in general practice
Correct answer: A. Donates electron density from filled d orbitals back into the CO pi* orbital (backbonding), strengthening M-C and weakening C-O
Explanation: Metal-CO: CO sigma-donates to M, and M pi-backdonates from filled d orbitals into CO pi*; this strengthens M-C bond and weakens C-O (IR shows lower C-O stretch vs free CO).
The three common coordination geometries: octahedral (6 ligands), tetrahedral (4 ligands), and square planar (4 ligands in one plane).
Concept context
Study of compounds where a central metal atom is bonded to surrounding ligands. Covers nomenclature, types of isomerism, bonding theories (VBT, CFT), and applications in medicine, photography, and industry.