Question

Explain effective atomic number (EAN) by an example.

Hint:

EAN helps in predicting the stability of metal complexes. If EAN matches the nearest noble gas configuration, the complex is stable.

Answer 1

Step 1: Definition of Effective Atomic Number (EAN) Effective Atomic Number (EAN) is the total number of electrons present around the central metal ion, including the electrons donated by ligands. \[ EAN = Z - O + 2C \] where:
- \( Z \) = Atomic number of metal
- \( O \) = Oxidation state of metal
- \( C \) = Number of ligands coordinated

Step 2: Example - Fe in \([Fe(CN)_6]^{3-}\)

For Fe in \([Fe(CN)_6]^{3-}\): \[ Z = 26, \quad O = +3, \quad C = 6 \] \[ EAN = 26 - 3 + 2(6) = 35 \]