The molecular geometry of CH2O, commonly known as formaldehyde, is trigonal planar.
Understanding CH2O's Structure
CH2O is a simple organic compound where carbon acts as the central atom, bonded to two hydrogen atoms and one oxygen atom. To determine its molecular geometry, we consider the arrangement of electron domains around the central carbon atom, as described by the Valence Shell Electron Pair Repulsion (VSEPR) theory.
- The central carbon atom forms a double bond with the oxygen atom and a single bond with each of the two hydrogen atoms. This results in three electron domains around the central carbon atom.
- A key factor in its geometry is that the core atom (carbon) of formaldehyde does not have any lone pairs of electrons. All its valence electrons are involved in bonding. The absence of lone pairs on the central atom allows for a symmetrical arrangement of the bonded atoms.
- While the oxygen atom in formaldehyde does possess two lone pairs of electrons, these lone pairs are on the terminal oxygen atom and do not directly influence the geometry around the central carbon atom.
Hybridization and Bond Angles
The carbon atom in CH2O undergoes sp2 hybridization. This type of hybridization leads to three sp2 hybrid orbitals that are oriented 120 degrees apart in a single plane.
- As a result, the bond angles within the CH2O molecule are approximately 120 degrees, which is characteristic of a trigonal planar structure.
- This arrangement minimizes electron repulsion among the three bonding domains, creating the most stable configuration. The molecular geometry of CH2O fits the AB3 type, where 'A' represents the central carbon atom and 'B' represents the surrounding atoms (two hydrogens and one oxygen).
Summary of CH2O Molecular Geometry
The table below summarizes the key characteristics contributing to the trigonal planar geometry of CH2O:
| Feature | Description |
|---|---|
| Chemical Formula | CH2O (Formaldehyde) |
| Central Atom | Carbon (C) |
| Number of Electron Domains | 3 (one double bond, two single bonds) |
| Lone Pairs on Central Atom | 0 |
| Hybridization of Central Atom | sp2 |
| Bond Angles | Approximately 120° |
| Molecular Geometry | Trigonal Planar |
