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 as a Member 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
- 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 triennial congresses, held in association with the business meetings of the union (General Assemblies), are attended by 1,500 to 3,000 scientists. The union also organizes or sponsors many smaller meetings.
It has formed 23 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 organizes many international projects concerned with the establishment of internationally acceptable standards or methods of procedure, and they organize specialist meetings or workshops 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 online pages a year and is divided into six sections. The crystallographic community owns and controls the journal and its sister publications, the Journal of Applied Crystallography, the Journal of Synchrotron Radiation, a flagship journal, IUCrJ, and a specialist data publication, IUCrData. 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. The ninth volume, Powder diffraction, published in 2019 and early chapters of the tenth, X-ray absorption spectroscopy and related techniques, are available online.
At present 52 national member organizations adhere to IUCr.