Welcome to the

International Union of Crystallography

The IUCr is an International Scientific Union adhering to the International Science Council. Its objectives are to promote international cooperation in crystallography and to contribute to all aspects of crystallography, to promote international publication of crystallographic research, to facilitate standardization of methods, units, nomenclatures and symbols, and to form a focus for the relations of crystallography to other sciences.

IUCr Newsletter

research news

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Special issue on electron crystallography

[B cover Aug 19]Structure analysis of micro- and nanocrystalline materials has witnessed immense progress in the last decade thanks to the development of electron diffraction techniques. The automation of data collection, development of new data collection modes and improvements in the data treatment have allowed unprecedented progress in most aspects of crystallography dealing with very small crystals. Probably the most notable change of paradigm is observable in the structure determination of unknown phases by electron diffraction. Three-dimensional diffraction techniques now allow almost routine solution and of structures from single crystals as small as a few tens of nanometres, providing access to hitherto unsolvable crystal structures or to previously unattainable level of structural detail. Scanning diffraction techniques allow phase and orientation mapping with nanometre resolution and even three-dimensional reconstruction of phase and orientation distributions.

This special issue of Acta Cryst. B features a collection of original contributions covering a broad range of aspects of electron crystallography. An interested reader will find papers describing the foundations and methodological basis of structure solution by electron diffraction, theoretical and methodological advances in data processing, discussion of applications of electron diffraction outside the realm of perfectly periodic crystals as well as specific case studies showing the application of the methods to hot topics in current crystallography.

The collection of contributions in this special issue showcases the diversity of applications of current electron diffraction techniques, demonstrates the state of the development of the technique and also features work that further advances the electron diffraction methods. We believe that this special issue can serve as a starting point for anybody interested in electron crystallography and we are convinced that the contributions in this issue will become reference points for future research in this exciting field.

Joke Hadermann and Lukáš Palatinus
Guest Editors

Posted 15 Aug 2019


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International Tables Volume H: Powder diffraction now available

We are pleased to announce the publication in print and online of the much-anticipated International Tables for Crystallography Volume H: Powder diffraction. This substantial volume, edited by C. J. Gilmore, J. A. Kaduk and H. Schenk, is the result of a huge amount of effort from the powder diffraction community, and we would like to thank the Editors and the authors for their outstanding dedication and hard work. 


Powder diffraction is the most widely used crystallographic method with applications spanning all aspects of structural science. This new volume of International Tables covers all aspects of the technique with over 50 chapters written by experts in the field. The 932-page volume contains seven parts:

  • Part 1 provides an introduction to the principles of powder diffraction.
  • Part 2 covers instrumentation for laboratory X-ray studies, synchrotron, neutron and electron diffraction, 2D diffraction and special environments (temperature, pressure, magnetic fields, reaction cells). Sample preparation is also covered.
  • Part 3 describes the different methodologies used in powder diffraction.
  • Part 4 covers structure determination and validation.
  • Part 5 discusses defects, texture and microstructure: stress and strain, grain size and thin films.
  • Part 6 provides a useful review of available software.
  • Part 7 describes applications to many areas of industrial and academic importance including macromolecules, zeolites, mining, ceramics, cement, forensic science, archaeology and pharmaceuticals. Both the theory and applications are discussed.
Volume H is the key reference for all powder diffractionists from beginners to advanced practitioners, and has been designed to be a practical volume without sacrificing rigour. Many examples of the method are discussed in detail and in several cases the data used are available to download.

Readers at institutions whose libraries have purchased perpetual access to the full set of International Tables will already have access to the online edition of Volume H. All the volumes are also available in print, with a 50% discount for IUCr Associates buying copies for personal use. For more information, please see here.

Posted 19 Jul 2019 


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An-Pang Tsai (1958-2019)

[An-Pang Tsai]It is with great sadness that we report that An-Pang Tsai passed away on 25 May 2019 at the age of 60.

He was a professor at Tohoku University, Sendai, Japan, and a leader in the field of quasicrystal and complex intermetallic research. His discovery of most of the known stable quasicrystals has been invaluable in understanding the structure and physical properties of these aperiodic crystals. Professor Tsai received many awards including the Medal of Honor with Purple Ribbon bestowed by the Japanese government.

He will be sorely missed by his many friends and colleagues in the crystallographic community. Our thoughts go to his wife, children and family.

Marc de Boissieu

This note has appeared in the IUCr Newsletter. A full obituary has been published in Acta Cryst. B.

Posted 05 Jul 2019 


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Cambridge Structural Database reaches one million structures

On 6 June 2019, the Cambridge Crystallographic Data Centre (CCDC) announced a huge milestone for structural chemistry with the addition of the millionth structure into the Cambridge Structural Database (CSD).

CSDThe millionth structure to enter the CSD, 1-(7,9-diacetyl-11-methyl-6H-azepino[1,2-a]indol-6-yl)propan-2-one (CSD Refcode XOPCAJ), and the IUCr's contributions to the CSD by journal.

The CSD is the world's repository of highly curated experimentally determined organic and metal–organic crystal structures. It is used globally by scientists in more than 70 countries to understand how molecules behave and interact in three dimensions in the solid form and ultimately how this affects physical properties.

The 1,000,000th structure is an N-heterocycle produced by a chalcogen-bonding catalyst activating multiple reaction steps sequentially. In the paper the authors describe a class of chalcogen-bonding catalysts that enable the assembly of discrete small molecules leading to the construction of N-heterocycles in a highly efficient manner. The structure was determined by Yao Wang and co-authors from Shandong University in China and published in the Journal of the American Chemical Society.

The IUCr has made a significant contribution to the growth of the CSD, having contributed nearly 90,000 structures; just under 50% of these were published in Acta Cryst. E.

Posted 11 Jun 2019 


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Nominations invited for membership of IUCr Executive Committee and IUCr Commissions

In Prague in 2020, the 25th General Assembly of the IUCr will elect the new members of the Executive Committee and the Commissions. The Executive Committee wishes its own nominations to be representative of the desires of the community of crystallographers at large. We are therefore inviting the National Committees for Crystallography to submit suggestions for the future membership of the IUCr Executive Committee and the Commissions. It is important to have a fair representation of our diverse community, including young scientists and women, on our Executive Committee and Commissions, and ask that you take this into account when submitting your nominations. These suggestions will then be considered by the Executive Committee when preparing its own nominations at its meeting in 2019.

Executive Committee

The vacancies to be filled are those of President, Vice-President, General Secretary and Treasurer and three ordinary members. None of the present holders of the offices to be filled are eligible for re-election to the same office. We invite you to make suggestions for each vacant office. Please feel free to suggest more than one person for any particular position. Although a National Committee has special knowledge of crystallographers in its own country, and we would be pleased to have suggestions based on this knowledge, it would also be helpful if you suggested candidates from other countries as well. The Executive Committee should be a fair representation of the variety of nationalities from the different continents that make up the membership of the IUCr and of the variety of fields and sub-disciplines in our science. A good gender balance is also important. The nomination form is available here; the submission deadline is 30 June 2019.

Non-publishing Commissions

The Executive Committee welcomes suggestions from National Committees for the Chairs and members of the non-publishing Commissions. The current memberships can be seen here. Your suggestions will be of great help to the Commissions when they compile their own recommendations, which form the basis from which the Executive Committee's nominations to the General Assembly for the Chairs and members of Commissions are compiled. The IUCr needs candidates who are willing to participate actively in the work of the Commissions, and it would be most helpful if you could include some brief information on the specific scientific interests of the persons you suggest. The nomination form is available here; the submission deadline is 30 June 2019.

Posted 04 Jun 2019 


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Michael G. Rossmann (1930-2019)

[rossmann]It is with great sadness that we report the death of one of the giants in the field of structural biology, Michael G. Rossmann. Professor Rossmann (Purdue University, West Lafayette, IN, USA) died on 14 May 2019 at the age of 88.

From mapping the structure of the common cold virus using X-ray crystallography in 1985 to creating the most accurate picture to date of the Zika virus using cryoelectron microscopy in 2018, he and his team have paved the way for vaccine design.

In 1994, Professor Rossmann received the Gregori Aminoff Prize, awarded by the Royal Swedish Academy of Sciences, for his fundamental methodological work on the utilization of non-crystallographic symmetry, with its especially important applications within protein and virus crystallography. Shortly afterwards, in 1996, he was awarded the fourth Ewald Prize for his work on molecular replacement and the use of non-crystallographic symmetry in the determination of macromolecular structure and for his research on the structure of viruses, which is foremost among the triumphs of crystallography. The latter Prize was presented during the Opening Ceremony of the 17th IUCr Congress (Seattle, WA, USA), and it was at this Congress that the IUCr commissioned him and Eddy Arnold to produce a new volume for the International Tables series dedicated to the growing field of macromolecular crystallography. The resultant Volume F, which appeared in 2001, was enthusiastically welcomed by the structural biology community. Professor Rossmann had other close ties to the IUCr. At the 12th General Assembly (Ottawa, Canada) in 1981, he was elected Chair of the new Commission on Biological-Macromolecule Crystallography (now Commission on Biological Macromolecules), and has also served on the Commission on Crystallographic Nomenclature. In addition, he has published widely in IUCr journals.

A full obituary will be published in due course.

Posted 15 May 2019