What is the lewis structure for GeCl6 -2 , what is the determine the hybridization on the center atom and what are the sigma and pi bonds.
The Correct Answer and Explanation is :
The Lewis structure for GeCl₆²⁻ involves placing germanium (Ge) as the central atom and six chlorine (Cl) atoms surrounding it. The negative 2 charge on the molecule indicates that two additional electrons are available for bonding.
Steps to Draw the Lewis Structure:
- Count the Valence Electrons:
- Germanium (Ge) is in Group 14, so it has 4 valence electrons.
- Each chlorine (Cl) atom is in Group 17, so each chlorine has 7 valence electrons.
- The 2 negative charges add 2 more electrons.
- Total valence electrons = 4 (from Ge) + 6 × 7 (from Cl) + 2 (from the charge) = 46 electrons.
- Place Germanium in the Center:
- Since Ge is the least electronegative element, it goes in the center, and the Cl atoms are arranged symmetrically around it.
- Distribute Electrons:
- Each Ge–Cl bond involves two electrons, with 6 bonds forming between Ge and the 6 Cl atoms. This uses 12 electrons.
- The remaining electrons are placed as lone pairs on the Cl atoms. Each Cl atom has 3 lone pairs (6 electrons), using up the remaining 34 electrons.
- Check for Octet Completion:
- Each Cl atom has 3 lone pairs and one bond, satisfying its octet.
- Germanium, being in the 4th period, can expand its octet, having 12 electrons in its valence shell (6 bonds × 2 electrons each = 12 electrons).
Hybridization of the Central Atom (Ge):
Germanium (Ge) in GeCl₆²⁻ has 6 bonds with chlorine atoms. The hybridization is sp³d², which involves the mixing of one s orbital, three p orbitals, and two d orbitals from the germanium atom to form six hybrid orbitals that bond with the chlorine atoms.
Sigma and Pi Bonds:
- Sigma Bonds: Each Ge–Cl bond is a sigma bond because it forms along the axis connecting the nuclei of the germanium and chlorine atoms.
- Pi Bonds: There are no pi bonds in GeCl₆²⁻ because all bonds are single bonds formed between the sp³d² hybrid orbitals of Ge and the p orbitals of Cl atoms.
Conclusion:
In GeCl₆²⁻, germanium (Ge) is the central atom with sp³d² hybridization, and it forms 6 sigma bonds with chlorine atoms. There are no pi bonds in this molecule. The structure involves a symmetrical arrangement of the chlorine atoms around the germanium atom, completing the octet for the chlorine atoms and utilizing an expanded octet for the germanium atom.