Parse the molecular formula
The molecule contains one carbon atom, two hydrogen atoms, and one oxygen atom.
Lewis Structure
Formaldehyde
CH2O has carbon in the center with two C-H bonds and one C=O double bond.
Use the diagram and steps below to check the formaldehyde Lewis structure, CH2O Lewis dot structure, valence electrons, formal charges, and molecular shape.
Formaldehyde
The molecule contains one carbon atom, two hydrogen atoms, and one oxygen atom.
Carbon contributes 4 electrons, hydrogen contributes 1 each, and oxygen contributes 6.
Hydrogen must be terminal, and carbon can connect to both hydrogens and oxygen.
Start with single bonds from carbon to the two hydrogens and to oxygen.
A C=O double bond completes carbon's octet, and oxygen keeps two lone pairs.
| Atom | Formal charge |
|---|---|
| C | 0 |
| O | 0 |
| H | 0 each |
The CH2O Lewis structure has carbon in the center with two C-H single bonds, one C=O double bond, and two lone pairs on oxygen.
The Lewis dot structure for CH2O is the electron-dot drawing shown above. The CH2O Lewis structure has carbon in the center with two C-H single bonds, one C=O double bond, and two lone pairs on oxygen.
CH2O has 12 total valence electrons in this Lewis structure.
CH2O has trigonal planar around c molecular geometry and trigonal planar around c electron geometry.
CH2O is polar in the Lewis structure shown here. Its molecular geometry is Trigonal planar around C.
Method notes are aligned with standard Lewis structure steps: count valence electrons, draw a skeleton, distribute electrons, form multiple bonds when needed, and check formal charges and resonance.
OpenStax Chemistry 2e: Lewis Symbols and Structures and Formal Charges and Resonance.