International Union of Pure and Applied Chemistry

The International Union of Pure and Applied Chemistry (IUPAC /ˈaɪjuːpæk, ˈjuː-/) is an international federation of National Adhering Organizations working for the advancement of the chemical sciences, especially by developing nomenclature and terminology. It is a member of the International Science Council (ISC). IUPAC is registered in Zürich, Switzerland, and the administrative office, known as the "IUPAC Secretariat", is in Research Triangle Park, North Carolina, United States. IUPAC's executive director heads this administrative office, currently Greta Heydenrych.

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 naming 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, but IUPAC has publications in many science 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 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 (CIAAW).

The need for an international standard for chemistry was first addressed in 1860 by a committee headed by German scientist Friedrich August Kekulé von Stradonitz. This committee was the first international conference to create an international naming system for organic compounds. The ideas that were formulated at that conference evolved into the official IUPAC nomenclature of organic chemistry. IUPAC is a legacy of this meeting, making it one of the most important historical international collaborations of chemistry societies. IUPAC as such was established in 1919.Since this time, IUPAC has been the official organization with the responsibility of updating and maintaining official organic nomenclature.

One notable country excluded from early IUPAC was Germany. Germany's exclusion was a result of prejudice towards it by the Allied powers after World War I. Germany was finally admitted into IUPAC in 1929. However, Nazi Germany was removed from IUPAC during World War II During World War II, IUPAC was affiliated with the Allied powers, but had little involvement with the war effort itself. East and West Germany were only readmitted to IUPAC in 1973. Since World War II, IUPAC has focused on standardizing nomenclature and methods in science.

In 2016, IUPAC denounced the use of chlorine as a chemical weapon. In a letter to Ahmet Üzümcü, director of the Organisation for the Prohibition of Chemical Weapons (OPCW), the organization pointed out their concerns in regards to chlorine weapon usage in the Syrian civil war and other places . The letter stated, "Our organizations deplore the use of chlorine in this manner. The indiscriminate attacks, possibly carried out by a member state of the Chemical Weapons Convention (CWC), are of concern to chemical scientists and engineers around the globe and we stand ready to support your mission of implementing the CWC." According to the CWC, "the use, stockpiling, distribution, development or storage of any chemical weapons is forbidden by any of the 192 state party signatories."

IUPAC is governed by several committees that all have different responsibilities. The committees are as follows: Bureau, CHEMRAWN (Chem Research Applied to World Needs) Committee, Committee on Chemistry Education, Committee on Chemistry and Industry, Committee on Printed and Electronic Publications, Evaluation Committee, Executive Committee, Finance Committee, Interdivisional Committee on Terminology, Nomenclature and Symbols, Project Committee, and Pure and Applied Chemistry Editorial Advisory Board. Each committee is made up of members of different National Adhering Organizations from different countries.

The steering committee hierarchy for IUPAC is as follows:

• All committees have an allotted budget to which they must adhere.
• Any committee may start a project.
• If a project's spending becomes too much for a committee to continue funding, it must take the issue to the Project Committee.
• The project committee either increases the budget or decides on an external funding plan.
• The Bureau and Executive Committee oversee operations of the other committees.

Scientists framed a systematic method for naming organic compounds based on their structures. Hence, the naming rules were formulated by IUPAC.

IUPAC establishes rules for harmonized spelling of some chemicals to reduce variation among different local English-language variants. For example, they recommend "aluminium" rather than "aluminum", "sulfur" rather than "sulphur", and "caesium" rather than "cesium".

IUPAC organic nomenclature has three basic parts: the substituents, carbon chain length, and chemical affix. The substituents are any functional groups attached to the main carbon chain. The main carbon chain is the longest possible continuous chain. The chemical affix denotes what type of molecule it is. For example, the ending ane denotes a single bonded carbon chain, as in "hexane" (C
₆H
₁₄).

Another example of IUPAC organic nomenclature is cyclohexanol:

• The substituent name for a ring compound is cyclo.
• The indication (substituent name) for a six carbon chain is hex.
• The chemical ending for a single bonded carbon chain is ane.
• The chemical ending for an alcohol is ol.
• The two chemical endings are combined for an ending of anol indicating a single bonded carbon chain with an alcohol attached to it.

Basic IUPAC inorganic nomenclature has two main parts: the cation and the anion. The cation is the name for the positively charged ion and the anion is the name for the negatively charged ion.

An example of IUPAC nomenclature of inorganic chemistry is potassium chlorate (KClO₃):

• "Potassium" is the cation name.
• "Chlorate" is the anion name.

IUPAC also has a system for giving codes to identify amino acids and nucleotide bases. IUPAC needed a coding system that represented long sequences of amino acids. This would allow for these sequences to be compared to try to find homologies. These codes can consist of either a one-letter code or a three-letter code.

These codes make it easier and shorter to write down the amino acid sequences that make up proteins. The nucleotide bases are made up of purines (adenine and guanine) and pyrimidines (cytosine and thymine or uracil). These nucleotide bases make up DNA and RNA. These nucleotide base codes make the genome of an organism much smaller and easier to read.

The codes for amino acids (22 amino acids and six special codes) are:

The Experimental Thermodynamics books series covers many topics in the fields of thermodynamics.

IUPAC color code their books in order to make each publication distinguishable.

IUPAC and UNESCO were the lead organizations coordinating events for the International Year of Chemistry, which took place in 2011. The International Year of Chemistry was originally proposed by IUPAC at the general assembly in Turin, Italy. This motion was adopted by UNESCO at a meeting in 2008. The main objectives of the International Year of Chemistry were to increase public appreciation of chemistry and gain more interest in the world of chemistry. This event is also being held to encourage young people to get involved and contribute to chemistry. A further reason for this event being held is to honour how chemistry has made improvements to everyone's way of life.

IUPAC Presidents are elected by the IUPAC Council during the General Assembly. Below is the list of IUPAC Presidents since its inception in 1919.

• CAS registry number
• Chemical nomenclature
• Commission on Isotopic Abundances and Atomic Weights
• European Association for Chemical and Molecular Sciences
• Institute for Reference Materials and Measurements (IRMM)
• International Chemical Identifier (InChI)
• International Union of Biochemistry and Molecular Biology (IUBMB)
• International Union of Pure and Applied Physics (IUPAP)
• List of chemical elements naming controversies
• National Institute of Standards and Technology (NIST)
• Simplified molecular-input line-entry system (SMILES)

• Official website