The International Union of Pure and Applied Chemistry (IUPAC) is the world authority on chemical nomenclature and terminology, including the naming of new elements in the periodic table; on standardized methods for measurement; and on atomic weights, and many other critically-evaluated data. For just over a century IUPAC has contributed to the diverse and interdisciplinary field that is chemistry. IUPAC unites chemists worldwide to fulfill their mission by fostering sustainable development, providing a common language for chemistry, and advocating the free exchange of scientific information.