Definition of E2 Molecules
E2 type molecules are characterized by having a specific arrangement of their electrons and molecular geometry.
Square Planar Geometry
A square planar shape is a molecular geometry where four atoms or groups are positioned at the corners of a square, with the central atom at the center. This geometry is commonly found in d8 transition metal complexes.
Example of E2 Square Planar Molecule
An example of an E2 type molecule with a square planar shape is:

• Nickel(II) Complex: [Ni(CN)4]²⁻
• Platinum(II) Complex: [PtCl4]²⁻

Characteristics of Square Planar Molecules
- Electron Configuration: Square planar complexes typically involve d8 electron configuration, where the d orbitals are filled in such a way that they lead to a stable planar arrangement.
- Hybridization: The central atom undergoes dsp² hybridization, incorporating one d orbital, one s orbital, and two p orbitals.
- Bond Angles: The bond angles in square planar geometry are 90° and 180°, leading to minimal steric hindrance between the ligands.
Importance in Coordination Chemistry
Square planar molecules are significant in coordination chemistry due to their unique electronic properties and applications in catalysis, materials science, and medicinal chemistry.
Conclusion
Understanding E2 type molecules with square planar geometry is crucial for the study of transition metals and their compounds, which have substantial relevance in various chemical reactions and industrial processes.