Draw the Lewis structure for COCl2, including lone pairs. What is the molecular shape of COCl2? The C – Cl bond in COCl2 is polar or nonpolar? What is the Cl – C – Cl bond angle? The molecule COCl2 is polar or nonpolar?
The Correct Answer and Explanation is :
Lewis Structure for COCl₂:
- Count Valence Electrons:
- Carbon (C): 4 valence electrons.
- Oxygen (O): 6 valence electrons.
- Chlorine (Cl): 7 valence electrons each (x2).
Total = 4 + 6 + (7 × 2) = 24 valence electrons.
- Draw the Skeleton Structure:
Place the carbon atom in the center (least electronegative) with single bonds to two chlorine atoms and a double bond to oxygen. - Distribute Electrons:
- Assign lone pairs to oxygen and chlorine to satisfy their octets.
- Carbon is surrounded by 8 electrons (2 from each bond).
- Final Lewis Structure:
- Carbon forms a double bond with oxygen (C=O) and single bonds with each chlorine atom.
- Oxygen has two lone pairs, and each chlorine atom has three lone pairs.
Molecular Shape:
- The central carbon has three regions of electron density (one double bond and two single bonds), resulting in a trigonal planar molecular shape.
C–Cl Bond Polarity:
- The C–Cl bond is polar because chlorine is more electronegative than carbon, creating a dipole moment toward the chlorine atom.
Cl–C–Cl Bond Angle:
- The bond angle in a trigonal planar geometry is approximately 120°.
Polarity of COCl₂ Molecule:
- The molecule is polar. Although the Cl–C–Cl bond angles are symmetric, the strong electronegativity difference between oxygen and carbon creates a dipole. The dipoles do not cancel out, resulting in an overall polar molecule.
Explanation:
The molecular structure and polarity of COCl₂ are derived from its Lewis structure and molecular geometry. The trigonal planar geometry arises because carbon forms three regions of electron density, and the electron pairs repel each other to maximize distance. The polar bonds (C=O and C–Cl) contribute to a net dipole moment, making the molecule polar. The asymmetry of the dipoles ensures the polar nature of COCl₂ despite its planar structure.