The formation of the International Union of Crystallography (IUCr) was discussed at an international meeting held in London in May 1946; the Union was admitted to ICSU on 7 April 1947. Its objectives are the following: to promote international cooperation in crystallography and to contribute to the advancement of all aspects of crystallography; to promote international publication of crystallographic research; to facilitate standardization of methods, units, nomenclature and symbols used in crystallography and to form a focus for the relations of crystallography to other sciences.
Since its formation, the Union has remained the focal point for international cooperation in crystallography. Its recent triennial congresses, held in association with the business meetings of the Union (General Assemblies) are attended by 2,000 to 3,000 scientists. The Union also organizes or sponsors many smaller meetings.
It has formed 18 Commissions, which are concerned with either a principal publishing activity or a major topic or field of concern to crystallographers. The second group of Commissions organize many international projects concerned with the establishment of internationally acceptable standards or methods of procedure. Also, they organize specialist meetings or short courses of instruction for young scientists.
The Union publishes its own international scientific journal, Acta Crystallographica, the major journal for publication of crystallographic research. Today it runs to 8,000 pages a year and is divided into five sections. The fifth section, Structure Reports Online, is an electronic-only journal, launched in January 2001. The crystallographic community owns and controls the journal and its sister publications, the Journal of Applied Crystallography and the Journal of Synchrotron Radiation. The Union appoints the editors of the journals and is solely responsible for the finances of these publications. Other major scientific publishing works of the Union are the International Tables for Crystallography which contain the theory of crystallographic groups (providing the basic reference work for all crystal structure determinations) and the mathematical, physical and chemical tables required for crystallographic work.
At present 40 national member organizations adhere to the Union.