Relativistic quantum chemistry is a complex subject that deals with the behavior of subatomic particles in a relativistic environment. It is a field of study that requires a deep understanding of quantum mechanics and Einstein's theory of relativity. Synonyms for this term include relativistic molecular calculations, relativistic electronic structure theory, and relativistic density functional theory. Each of these synonyms refer to different methods and techniques used in the study of relativistic quantum chemistry. Relativistic molecular calculations are used to study the behavior of molecules in relativistic environments, while relativistic electronic structure theory focuses on the electronic structure of atoms and molecules in these environments. Relativistic density functional theory is a mathematical approach used to calculate the energy and properties of materials and molecules in a relativistic context.