As we approach the end of 2025 and look ahead to 2026 and our 27th Congress and General Assembly, I would like to share a message of positivity and optimism about the future of our Union. I would also like to reaffirm the extraordinary contribution of science to a rapidly changing world, a world which can lead to feelings of alienation and nostalgia.

Every era has its own concerns, and our era needs scientists who believe in their societal role and can solve humanity's problems. Over the last 130 years, crystallographers have made key discoveries, and our Union has forged the necessary connections to enable highly effective global communication and collaboration. Some of us who are now passing the baton on to new generations knew the people who developed our discipline in the 1950s and 1960s, and we saw them recognised with Nobel Prizes. In 1985, Herbert A. Hauptman and Jerome Karle received the Nobel Prize in Chemistry, and in 2025, Susumu Kitagawa, Richard Robson and Omar M. Yaghi received the same prize. At the Madrid Congress in 2011, Omar Yaghi delivered a plenary lecture alongside Venkatraman Ramakrishnan, Thomas A. Steitz and Ada E. Yonath, who had won the Prize in 2009. A notable aspect of this year's Prize in Chemistry was the recognition of the contribution of metal-organic frameworks (MOFs) to global sustainability, demonstrating the connection between structural science and potential solutions to some of the most pressing problems that future generations will face.

In recognition of the unifying role of crystallography within the International Union, we believe that structural science is currently experiencing a period of significant growth, as the term 'structural science' best encapsulates the current state of our discipline, which encompasses all advances related to the structure and dynamics of matter in its various forms. The development of structural science is currently being influenced significantly by large synchrotron and neutron facilities, spectacular advances in electron microscopy and diffraction, and the growing impact of quantum crystallography. The two main branches of structural science — life science and materials science — are becoming increasingly intertwined and are collaborating through organisations such as our Union.

In 2025, I experienced the wide range of activities of our five regional associations (ACA, ECA, AsCA, LACA and AfCA) through their conferences, all of which had high levels of participation and excellent scientific and social standards. The same was true of the ACA and LACA meetings I attended in 2024. At these conferences, I witnessed the emergence of new generations of crystallographers and structural scientists who are bringing fresh ideas and approaches to our field. We are devising new programmes in which young people can demonstrate their scientific excellence. The AsCA Rising Star project is a good example of this, as are the ECA's innovative Scholarship and Mentoring programmes and the ACA's imaginative regional initiatives for engaging younger people through the Student Worker Program. All this work to integrate people and disciplines will come to fruition in the medium and long term, resulting in generations that are more globally connected and also connected to those who came before them and to society.

Preparations are under way for the 27th IUCr Congress and General Assembly in Calgary in 2026. We intend to give special prominence to the IUCr Early Career Scientists Division (ECSD) and IUCr Journals Early Career Boards, both of which are set to play a significant role in our future development. We would like to rejuvenate our editorial boards by adding young individuals with experience, and those in need of experience, who can help us identify ways to attract future scientists and inspire a scientific vocation from an early age. At the same time, we will celebrate the achievements of our Ewald, W. H. & W. L. Bragg and Struchkov award winners and hear from our Nobel laureates.

At our Journals Management Board meeting in Chester in March we will discuss the importance of maintaining rigorous standards in scientific evaluation and publication, as well as the engagement of Editors, Co-editors and referees in close collaboration with the Chester Editorial Team. We will also discuss the ongoing renewal of our editors and our global editorial strategy. In March, the Finance Committee will meet in Lund to discuss the important matter of maintaining the Union's financial health, which is essential for achieving our goals and providing funds for distribution by the Meeting Support Committee, now led by Maria Cristina Nonato following the excellent work of Manfred Weiss.

As always, I would like to express my deepest gratitude to everyone who contributes to our organisation, including the Adhering Bodies and Regional Associates, the IUCr Commissions and Committees, the Editors and Co-editors of our journals, the referees and the authors, our Chester staff, and all individual structural scientists. In the Congress Year, special thanks go to the IUCr2026 organisers.

Thanks also go to Mike Glazer, the Editor of the IUCr Newsletter, and his team, as well as to all our contributors, for making another issue possible that continues to serve as a reference point for communication within our community.

The arrival of a new year prompts thoughts about the future and the evolving nature of our endeavours. It is therefore important to adopt a positive outlook and strive for a more informed and fairer society — a goal that can only be achieved with the help of science. Let us hope that 2026 will be a year of progress and momentous discoveries for the future of our planet and all its inhabitants. Wherever we are and whatever our position, let us all contribute to this and feel proud to belong to the International Union of Crystallography. Happy 2026!

Dr Nessreen Abdelfatah Ali Abdoun recently completed the UNESCO–UNESRALE training programme, Remote Access to a Single-Crystal X-ray Diffractometer for African Scientists, hosted at the University of Lorraine, Nancy, France (1–26 September 2025).

Despite significant personal challenges due to the conflict in Sudan, Dr Abdoun describes the programme as a transformative experience. She gained hands-on training in remote instrument operation, data collection and structural refinement, leading to the successful analysis of four samples and the development of a new research proposal.

The course not only strengthened her own research capabilities but also reinforced her commitment to building crystallographic capacity in Sudan. Collaboration with fellow participants from Burundi, Cameroon, Côte d’Ivoire and Togo provided valuable insights into AFRAMED’s support and training initiatives.

Dr Abdoun extends her gratitude to UNESCO, the IUCr, CNRS and the University of Lorraine for enabling this opportunity.

Read the full report here.

We’re excited to share the latest CSD Data and Software release, featuring innovative tools and functionalities designed for our users.

The CSD Data update contains 1,413,222 entries (1,374,731 structures), with 46% organic and 54% metal-organic structures. 

The database has been further enhanced with important new fields, searchable in the CSD Python API and visible in Mercury. These fields include wavelength, resolution, Flack parameter and data availability.

The CSD Software update includes:

• Interaction networks, which allow users to find and visualize Periodic Bond Chains within a structure.
• PXRD Optimize functionality.
• Enhanced support of mmCIF files in our tools. GOLD can now produce output files in mmCIF.
• New prototype Python scripts.

Webinar: New tools and functionalities from the latest CSD Data and Software Release

Date: 22nd January 2026 at 16:00 (GMT)

Register

During this webinar, we will demonstrate the new tools and features introduced in the 2025.3 software release, focusing on interaction analysis, hydrogen bond propensity, and void network.

Free Virtual Workshops - 14th and 28th April, 12th May 2026

We’re excited to announce the dates for our first series of free virtual workshops in 2026! Get ready for insightful sessions, discover new tools, and connect with a global community.

Stay tuned — more details coming soon!

New Training Video: How to Select Atoms by SMARTS in Mercury!

Learn how to select atoms using SMARTS in Mercury by watching this 2-minute video.

You’ll learn how to:

✔️ Open Mercury and load a CSD structure.
✔️ Select a substructure using SMARTS.
✔️ Specify stereochemical configuration.

Sir Peter Hirsch, affectionally known as ‘PBH’ to his many friends, pioneered the use of transmission electron microscopy to study defects in crystals, particularly dislocations, and modelled the mechanical properties of a wide range of materials in terms of their defect structures. With his research student, Mike Whelan, he used electron microscopy to provide the first direct evidence of dislocations in crystals, a controversial hypothesis at the time. His research ranged from basic to applied and was underpinned by a deep understanding of crystallography. He had a huge influence on the field of materials science, both in the UK and internationally, and many people have commented to me that if there were a Nobel Prize in Materials Science, he would have won it. He was modest, kind, generous, laughed a lot and there was a twinkle in his eye.

Sir Peter’s life story is astonishing. He was born in 1925 in Berlin to Jewish parents. When he was nine, his parents divorced. His father died two years later, in 1936. On the night of 9 November 1938, Peter, aged 13, directly witnessed the events of Kristallnacht (the Night of Broken Glass), when German youths smashed windows and invaded the homes of Jewish families. Peter’s older brother, Hans, was already in the UK. His mother, who had remarried, devised a cunning plan to get herself and Peter out of Germany. She asked an English friend to send her a telegram demanding that she attend her son, Hans, in London with the fake news that he was seriously ill. So she travelled to London, leaving Peter behind in Berlin. Once in London, she arranged for Peter to be placed on a Kindertransport train, which arrived on 1 January 1939.

Peter went to Sloane Grammar School in Chelsea, knowing no English. However, he learned rapidly, excelled at science, and in 1943 he was offered a place at St Catharine’s College, Cambridge, where he studied Natural Sciences, specialising in Physics. He graduated with first-class honours in 1946 and joined the crystallography group of the Cavendish Laboratory, where, under W. H. (Will) Taylor, he obtained a PhD in 1951 on X-ray diffraction of work-hardened metals. His first postdoctoral position, funded by the National Coal Board, was on the crystallography of coal, research that is still cited today. He was appointed Assistant Director of Research in Physics in 1957, University Lecturer in 1958, and Reader in Physics in 1964. In 1965, with Howie, Whelan, Pashley, and Nicholson, he published Electron Microscopy of Thin Crystals, which remained the standard text on the subject for many years. The book had a yellow cover and was known as the ‘yellow bible’.

Peter was not only a great scientist but also a brilliant manager and organiser of his Metal Physics group in the Cavendish Laboratory. He was elected a Fellow of the Royal Society in 1963. In 1966, he was offered the post of Professor of Metallurgy and Head of Department of Metallurgy at both Cambridge and Oxford Universities. Cambridge had a large Metallurgy Department, the best in the UK, whereas the Oxford Department was very small. Peter told me that he chose Oxford because he relished the challenge of building it up. Peter moved to Oxford in 1966, becoming the Isaac Wolfson Professor of Metallurgy, Head of the Metallurgy Department, and a Fellow of St Edmund Hall. I was one of twelve people Peter took to Oxford from his Metal Physics group in Cambridge (I went as a postdoc). He was the Head of Department of Metallurgy (then Materials) at Oxford for 26 years, until his retirement in 1992, during which time he built up the department into the leading Metallurgy and Materials Department in the UK, and arguably the best in the world. Peter also developed strong links with leaders across many industries, and he was the Founding Chairman of Isis Innovation (now Oxford University Innovation), set up to exploit the University of Oxford's research. Peter was knighted in 1972 for “Services to Industry”.

Between 1982 and 1984, Sir Peter was the Chairman of the UK Atomic Energy Authority (UKAEA). This was a huge job at this critical time for the development of nuclear power in the UK, requiring substantial contact with government ministers and others. Peter loved science and his Department so much that he said he would only accept the job if it were part-time, so he could continue as Head of the Oxford Department. He also asked for a car and driver to take him from the Department to the UKAEA and to meetings elsewhere. Peter’s reputation was so high that his conditions were accepted. His chauffeur and car were often seen outside the Department waiting for him to finish a meeting. I was once in Peter’s office discussing a scientific problem when his secretary knocked on his door, entered and said that a government minister was on the phone to speak to him. Peter said “Tell him that I will call him back”.

Peter’s love of science was demonstrated in many other ways. For example, when he was away on holiday, he would ring members of his Department from a telephone box in the street to say “I’m ringing from a call box so my wife won’t find out. How is your experiment going?”

After his retirement, Sir Peter devotedly looked after his ill wife, who was in a wheelchair, for many years. However, to keep interacting scientifically with his colleagues, he arranged for a carer to look after her every Friday so that he could come into the Materials Department and discuss research, particularly with Professor Peter (Pete) Nellist. Pete recalls that, on Saturday mornings, Sir Peter would frequently phone him at home to suggest a solution to a problem they had been discussing the previous day.

Peter published his last first-author paper in 2013, when he was 88 (Hirsch et al., 2013). I was privileged to be an author, as was Pete Nellist. It describes a particularly complicated dissociation of a dislocation in GaN, imaged using high-resolution electron microscopy. All the authors struggled to understand the atomic structure of this dissociated dislocation. Sir Peter beat us all in solving this problem! He produced a 3D atomic model of the dissociated dislocation he had made at home using balls of plasticine for atoms! Remarkable!

Sir Peter celebrated his 100th birthday in 2025, with 100 guests, at a lunch at his Oxford college, St Edmunds Hall, which he gave for his friends. Although he used a walker, his mind was still very active, and he gave a brilliant speech!

Sir Peter was a scientific and engineering colossus. A truly great man. But he was also extremely modest, kind and generous. He helped so many people, particularly with his time. He loved to laugh and to greet people with a smile. His passing is the end of an era. 

References

Hirsch, P. B., Lozano, J. G., Rhode, S., Horton, M. K., Moram, M. A., Zhang, S., Kappers, M. J., Humphreys, C. J., Yasuhara, A., Okunishi, E. & Nellist, P. D. (2013). Philos. Mag. 93, 3925–3938. 

Charge density analysis is one important branch of crystallography research. The possibility of studying the electron density of crystal structures from experimental data can yield interesting insights from the perspectives of structural chemistry, materials science, pharmaceutical and drug chemistry, and other applications^[1].

Following its potentiality, charge density analysis of mineral structures from natural samples is one of the main interests of the Chemical Crystallography Group (GCQ) at the Federal University of Minas Gerais (UFMG) in Brazil. These structures are very diverse and present a large variety of chemical interactions in their crystal structures, and are relevant to geology and materials science. In this sense, we apply quantum crystallographic methods such as the Hansen-Coppens multipolar model (MM)^[2] and Hirshfeld Atom Refinement (HAR)^{[3, 4]} to describe these structures.

Recently, I was awarded the IUCR Best Poster Award at the LACA-ABCR 2025 meeting for my work “Charge Density Analysis of a Zircon (ZrSiO₄) Sample from Alcalino do Itatiaia, Brazil”. In the work, I studied a crystal of the mineral zircon and compared the results from the Isolated Atom Model and MM refinements^[2]. I also presented results from the topological analysis using the Quantum Theory of Atoms in Molecules (QTAIM) by Richard Bader^[5]. We obtained chemically reasonable atomic charges for the atoms from MM and QTAIM. The deformation maps showed the charge transfer from Zr and Si to O atoms. The maps also highlighted the difference between the Si-O and Zr-O bonds. The topological analysis enabled me to characterize the chemical bonds in the system, construct the molecular graph, and identify the critical points of the electron density.

It is really gratifying to get the award, and it shows the relevance of the work and that the topic we research is also interesting to the scientific community. Going further, we aim to expand our studies to other structures and keep applying the quantum crystallography models.

References

The 2025 Nobel Prize was awarded in Chemistry to Susumu Kitagawa, Richard Robson and Omar Yaghi "for the development of metal-organic frameworks".^[1] Early work was undertaken in the School of Chemistry at the University of Melbourne by Richard Robson. When Robson began this work, these network materials were referred to as coordination polymers. Robson was aided in these investigations by his long-time colleague and trusted collaborator, Bernard Hoskins. This article describes the origins of Robson's early work and how single crystal X-ray diffraction was used to characterise these new materials.

The original publication in the area, co-authored by Bernard Hoskins and Richard Robson, was a 1989 communication that was followed by a full article in 1990.^{[2, 3]} The 1990 paper opens with:

"In this section we present some simple structural ideas that appeared to us to have far-reaching implications with regard to the deliberate design and construction of a new and potentially extensive class of solid materials with infinite framework structures resembling scaffolding. We also put forward sensible reasons for expecting these new materials to show unusual and useful properties. The synthetic and crystallographic results presented in later sections represent some of our early attempts at the deliberate construction of infinite 3D frameworks. The results obtained provide considerable encouragement that a wide range of materials with scaffolding-like structures should prove synthetically accessible."

The early inspiration for this work can be traced to the 1970s when Robson was assigned the task of producing models of inorganic solids such as diamond, wurtzite, sodium chloride and rutile for use in first year chemistry lectures at the University of Melbourne. In the construction of the models, wooden balls were linked by metal rods. In order to give the intended structure, holes needed to be drilled into the balls at calculated positions to allow the rods to connect the spheres together. During the assembly process, it occurred to Robson that the wooden balls, with their drilled holes at specific geometric positions, were geometrically predisposed to perform specific structural roles within a targeted structure. After construction of the models, Robson was intrigued by the large space between the balls in the ball-and-stick models, but of course, in the dense inorganic solids these spaces do not exist.

As a coordination chemist, Robson wondered whether it was possible to generate crystalline solids in which the metal rods represented molecular links instead of single bonds. His early efforts involved the synthesis of a tetrahedral organic building block in which four 4-cyanophenyl groups are bound to a tetrahedral carbon centre. The four cyano groups are thus directed to the vertices of a tetrahedron. When combined with a metal centre that prefers tetrahedral coordination, such as Cu(I), a network material is generated that possesses the same underlying connectivity as diamond (Fig. 1). Instead of a dense inorganic solid, the resulting coordination polymer possesses large intraframework voids filled with highly disordered (essentially liquid) solvent molecules and uncoordinated counterions. The solvent filled voids occupy ~2/3 of the crystal volume.

This early success prompted investigations using different solids as topological models. For example, using PtS as a model, an open network crystalline material was generated in which planar 4-connecting Cu(II)[tetra(4-pyridyl)porphyrin] units are linked by tetrahedrally coordinated Cu(I) centres.^[4] Similarly, networks were generated by linking the trigonal ligand tricyanomethanide with octahedral divalent metal centres, which correspond to the trigonal oxide ions and octahedral Ti(IV) centres, respectively, in rutile, TiO₂.^{[5, 6]}

Over the years, other network topologies were explored. Often the topological model was a common inorganic solid but other nets corresponding to more obscure crystalline solids were also used. In this regard, the work of A. F. Wells was instructive. In his book, Structural Inorganic Chemistry, Wells surveys the field of inorganic structures and systematically describes a vast number of inorganic solids with a strong emphasis on the connectivity of these materials.^[7] In 1977 and 1979 he published two further books in which he focuses on a mathematical description to describe the connectivity.^{[8, 9]} These books served not only to assist in the design of new network materials but also proved useful in describing the underlying connectivity in complex coordination polymers.

With Robson focusing on the design and synthesis of these unique crystalline materials, Hoskins was responsible for the structural characterisation using single crystal X-ray diffraction. Hoskins started in the Department of Inorganic Chemistry at the University of Melbourne in the mid-1960s following a post-doctoral appointment at Oxford University with Nobel Prize winner Dorothy Hodgkin. Upon his arrival, Hoskins established a vibrant X-ray crystallography laboratory at the University of Melbourne. He was a meticulous and insightful researcher with a deep understanding of small molecule crystallography. Over four decades he trained numerous research students in crystallography, many of whom established themselves as distinguished crystallographers.

Small molecule crystallography in the late 1980s and 90s was particularly challenging and often required the input of a specialist crystallographer in regard to the handling of crystals, measurement of data and structure determination. When Hoskins first began work on Robson's crystals, the instrument in use was an Enraf-Nonius CAD4 diffractometer. Whilst this was a beautifully engineered instrument, its point detector allowed the intensity of only one reflection to be measured at a time. As a consequence, data collections typically took days and sometimes weeks to complete.

The new network materials presented additional challenges. Crystals commonly contained large regions of solvent, which could be lost upon removal from the mother liquor, leading to a deterioration in the crystal quality. Cooling of crystals immersed in a protective oil was seldom performed because the cryogenic equipment at the time was extremely temperamental. As a result, the crystallographer relied upon mounting a crystal in a Lindemann glass capillary tube along with a small quantity of the solution from which it was obtained, to protect the crystal from solvent loss. Whilst good quality diffraction was commonly evident at low 2θ angles for the open framework structures, there was often a paucity of higher angle data.

The highly disordered solvent could seldom be modelled, with Fourier difference maps indicating broad smears of electron density rather than clearly defined peaks. This was at a time before Anthony Spek's invaluable SQUEEZE tool was in widespread use.^[10] As a result of the disordered solvent, elevated R values were a common occurrence for these framework materials and referees regularly queried the high R values. Analysis of diffraction data often revealed high symmetry, and it was not uncommon to find solutions in multiple space groups that shared the same Laue symmetry and systematic absences. Manual determination of the correct space group was sometimes challenging but a 1995 paper of Richard E. Marsh provided instructive advice that regularly guided space group selection.^[11]

Refinements of structures, particularly those with large data sets and high numbers of parameters, were very time-consuming given the limitations in computer power. The representation of structures using ORTEP could be a slow, laborious process requiring the specification of atoms and symmetry operations in unforgiving fixed format files. Nevertheless, the program yielded high quality black and white images. One of the advantages of using ORTEP was that the user gained a deep appreciation of the underlying symmetry of the network material.

In the last 35 years there have been enormous advancements across all areas of X-ray crystallography with the improvement in diffractometer hardware probably the single most important development. When Robson and Hoskins first started working on network systems, the queue for the diffractometer as well as the time to measure a dataset were the rate determining steps in obtaining results. Remarkable advancements in computer hardware and software have streamlined the process enormously but it is interesting to note that the group still utilises various SHELX programs.^[12]

It is both satisfying and astonishing to see how the field of coordination polymers and metal-organic frameworks has developed. There appears to be no limit to the type of framework materials that can be synthesised. We are restricted only by our imaginations in generating materials that can be tailored for specific purposes. Despite all these changes and advancements, it appears that single crystal X-ray diffraction will continue to have an important role in driving this field forward, deep into the 21st century. Sadly, Bernard Hoskins passed away in 2002 and never lived to see the maturation of the field and its global impact.

References

2. Hoskins, B. F. & Robson, R. (1989). J. Am. Chem. Soc. 111, 5962–5964.

3. Hoskins, B. F. & Robson, R. (1990). J. Am. Chem. Soc. 112, 1546–1554.

4. Abrahams, B. F., Hoskins, B. F., Michail, D. M. & Robson, R. (1994). Nature 369, 727–729.

5. Batten, S. R., Hoskins, B. F. & Robson, R. (1991). J. Chem. Soc. Chem. Commun. pp. 445-447.

6. Batten, S. R., Hoskins, B. F., Moubaraki, B., Murray, K. S. & Robson, R. (1999). J. Chem. Soc. Dalton Trans. pp. 2977–2986.

7. Wells, A. F. (1984). Structural inorganic chemistry, 5th ed. Oxford University Press.

8. Wells, A. F. (1977). Three-dimensional nets and polyhedra. New York: Wiley.

9. Wells, A. F. (1979). Further studies of three-dimensional nets, ACA Monograph No. 8. New York/Pittsburgh: American Crystallographic Association.

10. Spek, A. L. (2015). Acta Cryst. C71, 9–18.

11. Marsh, R. E. (1995). Acta Cryst. B51, 897–907.

12. Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.