The International Union of Pure and Applied Chemistry (IUPAC, on lowercase letters: iupac, or ) is an international federation of National Adhering Organizations that represents chemists in individual countries. It is a member of the International Council for Science (ICSU). The international headquarters of IUPAC is in Zürich, Switzerland. The administrative office, known as the “IUPAC Secretariat”, is in Research Triangle Park, North Carolina, United States. This administrative office is headed by the IUPAC executive director. As of 1 August 2012, the Executive Director is Dr. John D. Petersen. IUPAC was established in 1919 as the successor of the International Congress of Applied Chemistry for the advancement of chemistry. Its members, the National Adhering Organizations, can be national chemistry societies, national academies of sciences, or other bodies representing chemists. There are fifty-four National Adhering Organizations and three Associate National Adhering Organizations. IUPAC’s Inter-divisional Committee on Nomenclature and Symbols (IUPAC nomenclature) is the recognized world authority in developing standards for the naming of the chemical elements and compounds. Since its creation, IUPAC has been run by many different committees with different responsibilities. These committees run different projects which include standardizing nomenclature, finding ways to bring chemistry to the world, and publishing works. IUPAC is best known for its works standardizing nomenclature in chemistry and other fields of science, but IUPAC has publications in many fields including chemistry, biology and physics. Some important work IUPAC has done in these fields includes standardizing nucleotide base sequence code names; publishing books for environmental scientists, chemists, and physicists; and leading the way in improving education in science. IUPAC is also known for standardizing the atomic weights of the elements through one of its oldest standing committees, the Commission on Isotopic Abundances and Atomic Weights.