Definition and Examples of a Molecule

The terms molecule, compound, and atom can be confusing! Heres an explanation of what a molecule is (and is not) with some examples of common molecules. Molecules form when two or more atoms form chemical bonds with each other. It doesnt matter if the atoms are the same or are different from each other. Examples of Molecules Molecules may be simple or complex. Here are examples of common molecules: H2O (water)N2 (nitrogen)O3 (ozone)CaO (calcium oxide)C6H12O6 (glucose, a type of sugar)NaCl (table salt) Molecules Versus Compounds Molecules made up of two or more elements are called compounds. Water, calcium oxide, and glucose are molecules that compound. All compounds are molecules; not all molecules are compounds. What Is Not a Molecule? Single atoms of elements are not molecules. A single oxygen, O, is not a molecule. When oxygen bonds to itself (e.g., O2, O3) or to another element (e.g., carbon dioxide or CO2), molecules are formed. Learn more: Types of Chemical BondsList of Diatomic Molecules