The Z-matrix defines the position of each atom relative to others using bond lengths, bond angles, and dihedral angles. The following table represents the internal coordinates for Formaldehyde in a standard Z-matrix format:
| Atom | Reference Atom (Bond) | Bond Length (Å) | Reference Atom (Angle) | Bond Angle (°) | Reference Atom (Dihedral) | Dihedral Angle (°) |
|---|---|---|---|---|---|---|
| C | - | - | - | - | - | - |
| O | 1 | 1.21 | - | - | - | - |
| H | 1 | 1.10 | 2 | 122.0 | - | - |
| H | 1 | 1.10 | 2 | 122.0 | 3 | 180.0 |
Note: Atom 1 is Carbon, Atom 2 is Oxygen, and Atoms 3 and 4 are the Hydrogens.