Chemical compound

A chemical compound is a substance formed when atoms of two or more elements bond together in fixed proportions, creating new properties distinct from its constituents. Water (H₂O) is the quintessential example—hydrogen and oxygen are both gases, yet together they form a liquid essential to life.

Compounds differ fundamentally from mixtures: their atoms are chemically bonded, not merely jumbled together. This bonding follows precise rules governed by electrons and the periodic table. A compound has a definite composition, a specific structure, and reproducible properties wherever it exists.

Compounds are the building blocks of reality. Organic compounds underpin all known life. Iron oxides shaped geology. Fossil fuels powered civilization. Even the Ozone layer protecting us is a compound—O₃—formed when UV radiation reshapes oxygen molecules.

Chemical compounds can be named systematically through IUPAC nomenclature, allowing scientists worldwide to communicate precisely. Understanding how compounds form, react, and transform is the heart of chemistry.

Related

Chemical reaction, Bonding, Molecular structure, Elements, Stoichiometry, Phase (matter)