Electron accountancy
Subject classification: this is a chemistry resource. |
Type classification: this is a lesson resource. |
Aims
editThis Lesson will cover:
- Revision of electron counting methods
- The Covalent Bond Classification as an alternative method
- Simple classes of ligand and bond ambiguities
- Curly arrow conventions in complexes
- Composite ligands
- Formal oxidation state and the d-electron count
- Coordination number and ambiguities
Classes of ligand
editL ligands (2e donors)
edit- PR3, N2, C2H4, CO, H2, C2H2
- observed as neutral
X ligands (1e donors)
edit- H, halides, R (alkyl), Ar (aryl), COR (acyl), OR (alkoxides), NR2
- observed as anions
Composite ligands
editElectron counting
editThe number of electrons donated by the metal = its group number.
Valence Number (VN)
VN = number of X ligands + charge on complex |
Coordination Number (CN)
CN = number of atoms bonded to the metal CN = number of electron pairs added to the metal CN = number of ligands bonded to the metal |
Ligand Bond Number (LBN)
LBN = sum of L and X ligands |