Stereochemistry

Stereochemistry, a subdiscipline of chemistry, studies the spatial arrangement of atoms that form the structure of molecules and their manipulation. The study of stereochemistry focuses on the relationships between stereoisomers, which are defined as having the same molecular formula and sequence of bonded atoms (constitution) but differing in the geometric positioning of the atoms in space. For this reason, it is also known as 3D chemistry—the prefix "stereo-" means "three-dimensionality" because many of the types of stereochemistry are based on 3D geometric relationships. Stereochemistry applies to all kinds of compounds and ions, organic and inorganic species alike. Stereochemistry affects biological, physical, and supramolecular chemistry.

Stereochemistry also studies the reactivity of the molecules in question (dynamic stereochemistry).

Cahn–Ingold–Prelog priority rules are part of a system for describing a molecule's stereochemistry. They rank the atoms around a stereochemical region of a molecule in a standard way, allowing unambiguous descriptions of their relative positions in the molecule.