Definition

Noun: A symbolic representation of the composition of a chemical compound. It uses atomic symbols and numerical subscripts to show the types and numbers of atoms present in a single molecule or formula unit of the substance.

Usage

A chemical formula is written to precisely define the elemental makeup of a pure substance. It is a fundamental notation in chemistry.

Examples

• The chemical formula for water is H₂O.
• Sodium chloride has the chemical formula NaCl.
• You can determine the molar mass from the chemical formula.

Advanced Usage

• Empirical Formula: A type of chemical formula that shows the simplest whole-number ratio of atoms in a compound. For example, the empirical formula for benzene is CH, while its molecular formula is C₆H₆.
• Molecular Formula: A type of chemical formula that indicates the exact number of each type of atom in a molecule. Glucose has the molecular formula C₆H₁₂O₆.
• Structural Formula: A representation that shows not only the number and type of atoms but also the arrangement of atoms and the bonds between them.

Variants and Related Words

• Formula (n): In a scientific context, this is often used as a shorter form of "chemical formula." It can also mean a general mathematical or scientific rule expressed in symbols.
• Empirical Formula (n): The simplest formula.
• Molecular Formula (n): The exact formula for a molecule.
• Structural Formula (n): A formula showing atom connectivity.

Synonyms

• Molecular Formula (when referring specifically to that type).
• Composition Notation.

Notes on Different Meanings

The word formula alone has broader meanings outside of chemistry, such as a method or procedure for achieving something (e.g., a formula for success), or a mathematical relationship. The term chemical formula is specific to chemistry.

Noun

1. a representation of a substance using symbols for its constituent elements