structural formula

The structural formula of a chemical compound is a graphical representation of the molecular structure, showing how the atoms are arranged. The chemical bonding within the molecule is also shown, either explicitly or implicitly. There are three common representations used in publications: text, Lewis type and line-angle formula. Also several other formats are used, as in chemical databases, such as SMILES, InChI and CML.

Unlike chemical formulae or chemical names, structural formulas provide a representation of the molecular structure. Chemists nearly always describe a chemical reaction or synthesis using structural formulae rather than chemical names, because the structural formulas allow the chemist to visualize the molecules and the changes that occur.

Many chemical compounds exist in different isomeric forms, which have different structures but the same overall chemical formula. A structural formula indicates the arrangements of atoms in a way that a chemical formula cannot.