Illustrated Glossary of Organic Chemistry

Tetravalent: An atom having four covalent bonds.

In this molecule the hydrogen atom and chlorine atoms are monovalent, the oxygen atom is divalent, the nitrogen atom is trivalent, and the carbon atom is tetravalent.

This molecule contains three tetravalent carbon atoms. The carbon atom of the methyl group has four single bonds. The carbon atom of the carbonyl group has two single bonds and one double bond. The carbon atom of the nitrile group has one single bond and one triple bond. A tetravalent carbon can also has two double bonds, for example, in carbon dioxide.