Chemical formulas

Compounds and molecules consist of multiple atoms which are bonded together. Chemical formulas describe the type and amount of these atoms.

Take, for instance, the chemical formula of water: H₂O. The formula shows that water consists of one oxygen (O) and two hydrogens (H). The number of each element is given as a subscript after each element unless the number is 1 (as for oxygen).

There are three main types of chemical formulas, which contain a varying degree of structural information:

• Empirical formulas: the lowest whole-number ratio of atoms in the compound
• Molecular formulas: the total number of each atom type in a molecule
• Structural formulas: an extended molecular formula giving information about the clustering and/or bonding between atoms