What is the molecular geometry of carbon dioxide, CO2?
The Correct Answer and Explanation is:
The molecular geometry of carbon dioxide (CO₂) is linear.
Explanation:
Carbon dioxide (CO₂) consists of one carbon atom and two oxygen atoms, with the molecular formula O=C=O. To understand its geometry, we must analyze the molecule’s bonding and electron pair distribution using VSEPR (Valence Shell Electron Pair Repulsion) theory.
- Lewis Structure:
In CO₂, the carbon atom forms double bonds with each oxygen atom. The Lewis structure can be drawn as O=C=O, with no lone pairs on the carbon atom and two lone pairs on each oxygen atom. - Electron Domain Geometry:
The carbon atom in CO₂ has two regions of electron density around it — one from each of the double bonds with the oxygen atoms. According to VSEPR theory, electron pairs (bonding or non-bonding) repel each other and arrange themselves as far apart as possible to minimize repulsion. In this case, there are two regions of electron density, which means the electron pairs will align linearly, 180° apart. - Molecular Geometry:
Since there are no lone pairs on the central carbon atom, the molecular geometry is determined solely by the positions of the atoms themselves. With two electron-dense regions positioned linearly around the central atom, the geometry of CO₂ is linear. This means the bond angle between the two oxygen atoms is 180°, and the molecule has a straight-line shape. - Symmetry and Polarity:
Due to the linear arrangement of the oxygen atoms and their equal electronegativity, the polarities of the two C=O bonds cancel each other out, resulting in a nonpolar molecule overall.
Thus, the molecular geometry of CO₂ is linear, with a bond angle of 180°. This geometry minimizes electron pair repulsions and gives the molecule its characteristic straight-line shape.