George Michael Sheldrick was not only the brilliant mind behind all that is SHELX, and an original scientist, enthusiastic for problem solving, but also an ideal collaborator, mentor and professor, with a wonderful sense of humour and deep humanity. George has touched the lives and careers of so many scientists, extending success, providing a sheltered and free work environment. He was always receptive to new ideas, encouraging independence, supportive and fair in his recognition of credit and ownership. His SHELX software has transformed crystallography, empowering researchers across chemistry, mineralogy and biology.

Figure 1. George M. Sheldrick and the diffractometer Quatermass (in the background), which was designed and built from components from many manufacturers to boost its functionality. George had a broad interest in science and occupied his bright mind with problem solving in structural chemistry. Possibly, he was a scientist from his birth in Huddersfield, Yorkshire. He was certainly a chess player before becoming a chemist.

1. Success for all

Success for all was the motto of Huddersfield New College, George's school in the town where he was born, which had been led from 1909 to 1936 by the chess master Henry Ernest Atkins. George not only learned chess and German there, he graduated in a much larger number of courses than was needed, or indeed usual, obtaining nine O-levels, six A-levels and two S-levels. At A-level, he achieved a distinction (the highest grade) in physics, mathematics and chemistry. George was awarded a Major Scholarship to study at Jesus College, Cambridge; at the time he was the only student in Jesus College to come from a non-private school. The school seems to have had a lasting influence. If the motto encapsulates a school's ethos and guiding principle, George took it with him throughout his career.

2. You have to choose between playing chess and playing chemistry

At Cambridge University, George continued to pursue his interest in chess and he took the natural sciences courses, common for a number of terms in mathematics, physics and chemistry. He specialized in the latter in his final year, attracted by structural chemistry and the cutting-edge methods being developed in Cambridge. Structure was providing invaluable information to understand the versatile chemical bonding displayed in inorganic compounds. George worked on various modern structural methods when these were still in their early stages, writing computer programs for all the required calculations. Later on, as a professor, his structural chemistry lectures in Göttingen were exceptionally inspiring: George had been present at the beginning of modern structural methods and his course proposed puzzles and exercises along with the illustration of principles.

His PhD thesis entitled NMR Studies of Inorganic Hydrides (1966) was supervised by Evelyn Ebsworth, who influenced his career by confronting him with the need to choose his focus. Fortunately for crystallography, he decided against becoming a professional chess player. As part of his PhD, George prepared silyl phosphines and arsines, the structures of which were unknown. The difficulties associated with this study of extremely poisonous and pyrophoric compounds may not be obvious to modern chemists. The absence of certain signals in the P(SiH₃)₃ infrared and Raman spectra led to the conclusion that the experiment was consistent with a planar configuration of the heavy atoms.

After his thesis, he took the opportunity to reinvestigate the structures using electron diffraction in the gas phase, contacting Durward Cruickshank at the University of Glasgow. Cruickshank generously shared his equipment and notes on refinement routines, later acknowledged by George for providing the nucleation point to start his SHELX work. Electron diffraction established the pyramidal instead of planar environment at the central atom and the paper by Beagley et al. (1968) adds to this conclusion: The structural results do demonstrate the dangers of making geometrical predictions on the basis of the absence of bands in i.r. or Raman spectra, since these may simply be too weak to be observed.

Figure 2. Cruickshank Symposium, UMIST, in September 1984. Front row, from left to right: Professor J. D. Dunitz FRS, Professor G. A. Jeffrey, Professor Dorothy Hodgkin FRS, Professor D. W. J. Cruickshank FRS, Professor Mary R. Truter. Behind: Professor K. N. Trueblood, Professor F. L. Hirshfeld, Dr J. S. Rollett, Professor J. E. Boggs, Professor A. C. T. North, Professor O. Bastiansen, Dr G. S. Pawley, Dr J. R. Helliwell, Professor G. M. Sheldrick (FRS 2001).

After his PhD in 1966, George was elected a Fellow of Jesus College. When Ebsworth left Cambridge to become Professor in Edinburgh, George, just 25 years old, shouldered the weighty responsibility of supervising his remaining PhD students during the completion of their work.

Figure 3. It was in Cambridge where George met the love of his life, Katherine Elizabeth Herford. They were married in Jesus College on 13 July 1968.

During this period, the structure of Fe(CO)₅ was determined by electron diffraction in the gas phase and published in Acta Crystallographica Section B (Beagley et al., 1969), showing that Acta Crystallographica journals were never limited to crystallographic studies alone but have structural questions at heart.

3. SHELX before SHELX-76

SHELX has transformed crystallography, empowering researchers across chemistry, mineralogy and biology. In one of the most cited papers ever (Sheldrick, 2008), George describes the birth of the SHELX programs. While typically our publications are scored by the impact factor of a journal, this paper rocketed the impact factor of the journal Acta Crystallographica Section A from 2.05 to 54, surpassing that of Science, Nature or Cell in the years 2009 and 2010. This establishes how many scientific projects must have been aided by George's insightful work and singular solutions. A work that is unstoppable because George has left a legacy not only in his methods and in the achievements they have mediated, but also in training and shaping the next generation of scientists building on his example.

The Short history of SHELX (Sheldrick, 2008) relates the technical innovations that were introduced, but understates the epic quest for solutions to overcome the extreme limitations of computing at the time, when it was not a matter of a program being faster, but whether a given calculation was possible at all.

One example involves the PDP8 computer controlling the Stoe two-circle diffractometer installed in 1969, with its small 4 kb memory. George's program, written to replace the limited one supplied with the machine, filled all the memory, which in the absence of additional physical storage had to hold all the required instructions and data; input and output were on punched paper tape. The issue with filling the memory is that, if written in assembly code and translated by the assembler, this compiler would need to occupy some of the memory itself. Hence George translated his code directly into octal (binary code with bits combined together in threes so that they had a value between 0 and 7), so that each program step was a 4-digit instruction or item of data between 0000 and 7777. Such was the shortage of memory that George used some program instructions to double up as numerical data constants if they happened to have the right value, and so he managed to pack everything necessary for the calculation into the tiny space. At this point, a disclaimer is needed for the benefit of newcomers: this is considered very bad programming practice and should not be emulated… but `needs must' and under dire straits it worked!

Another trick George used in his Fortran programming at a time when computer memory was limited (the 1970s and 80s with multi-user computers) was a standard option that large programs could be divided into smaller segments with one core section and others that could be called to overwrite each other. These were called overlays and the process was called chaining. Programming the control of a four-circle Syntex P21 diffractometer, George managed to make the program alter itself during execution, something that would not have been possible with a higher-level language such as Fortran, but in binary everything was valid! This allowed him to provide the multiple measurements needed for absorption correction, which would otherwise have required a separate program with the available hardware.

SHELX literally shaped the way in which crystallography was practised, fundamentally changing the routine in a chemical laboratory. A number of laboratories had programs to compute crystallographic operations, but typically they were case-specific calculations for the problem under study, that addressed individual steps involved. This extended calculations as results from one step would be needed for the next one. George contrived generally applicable solutions (e.g. valid for all space groups) to all necessary operations, compact enough to fit the limits of computers. The time required for any refinement operation on the fastest, state-of-the-art mainframe computers in Cambridge would occupy at least one night. Integrating the different steps required engendered a routine where the day would be dedicated to setting up experiments, interpreting results, solving problems and designing calculations that would run through the night. His free-variables to encode chosen parameters introduced flexibility. And to top it all they were user-friendly, including free-format input and were well documented. In the words of many crystallographers, George democratized X-ray crystallography.

Figure 4. From the start, SHELX was user-friendly: well documented and supported. On submitting this manuscript, SHELX-76 was downloaded from the IUCr website https://www.iucr.org/resources/commissions/crystallographic-computing/software-museum. The source was compiled with ifort -f66 SHELXN.FOR (SHELXN.FOR is the shelx76 version extended in 1977 to address neutron scattering) and worked out of the box testifying George's philosophy: zero dependencies and upwards compatibility.

It is clear why the cases for which SHELX was developed represented milestones: after all, even Julius Caesar had to add the fact that he saw between his coming and conquering! Application of the gaze on chemistry developed by George illustrates the kind of breakthrough that SHELX made possible in Cambridge then and later worldwide. Two examples of important problems solved in collaboration with Olga Kennard should be mentioned. DNA at atomic resolution was seen for the first time in the de­oxy-tetranucleotide (dAdTdAdT) that was phased beginning with only two comparatively light phosphor­us atoms from the Patterson analysis and applying tangent expansion, which would eventually become the routine TEXP in SHELXS (Viswamitra et al., 1978). A degradation product of the natural antibiotic vancomycin, then and now a last resort antibiotic, would yield a first characterization, needed to allow chemistry to target synthetic analogues as well as understanding of its mode of action binding to the bacterial cell wall (Sheldrick et al., 1978).

4. An expert is someone who has made all possible errors once – George Sheldrick

George was always willing to help with the solution of crystallographic problems, in a way that also transmitted his knowledge and thus promoted the training and independence of the recipient. In addition to sharing his programs with other laboratories, he would provide help at the same time imparting insight and tools on how his solution to a problem was contrived. George was very patient and encouraging, although with particularly catastrophic errors (chemistry getting out of control or a diffractometer collision) he would add but you do not need to repeat this one.

George applied for the Inorganic Chemistry university chair in Göttingen in 1975, when he was 33. As usual for such appointments, the process was delayed for a couple of years and, by the time he was offered the chair, Cambridge could not believe that the Sheldricks – who had only recently bought a house and had a young baby – were leaving for Göttingen.

In Göttingen, George had a state-of-the-art computer but it would take a couple of years to acquire a diffractometer. From the start, the mentoring of emergent scientists, supported to develop their own research within the German Habilitation system and other schemes, was an essential part of George's activities. Working with him was inspiring and fun; it covered a broad range of interests in chemistry, geology and biology evolving over the years. He was always receptive to our ideas, encouraging our independence, providing the means to support them and giving us credit for what we accomplished. At the same time, we were spared the financial worries or conflicts that were common in many institutes. If Goethe was right in writing that `character is built in the tempest of life while talent requires the calm', George shaped the optimal environment to develop our talents. (Some of us were occasionally more proactive than we should have been in generating opportunities to develop character. But George did not interfere in arguments and trusted us to outgrow pointless conflicts.) In Cambridge and Göttingen, George closely supervised more than a hundred theses. He supported attendance of his group at conferences not only as part of their training, but also to assist in achieving their career goals, for instance by meeting possible supervisors in person before applying for a postdoctoral position. This is clearly not to the benefit of the laboratory that loses their members but benefits the scientific community in general. These personal contacts were crucial as any poor choice might be a blow to career expectation.

One unusual trait George had was that he always pondered what people said, not who said it. Experience shows that humans are more ready to value what their friends, allies and authority figures state as being correct and search for reasons why their competition must be wrong! This lack of prejudice may explain why George's research group was always most diverse: he gave everyone fair opportunities. Listening to colleagues at conferences and reading their papers with impartiality prompted him to try out their ideas in his programs. He would not criticize if such ideas were unsuccessful in his tests but would adopt them if successful and give generous credit to the originators, publicising their work. No wonder that as a member of George's group one enjoyed a generally positive attitude from the community.

Among all collaborations, the prolific co-operation with his colleague in the Institute of Inorganic Chemistry, Professor Herbert W. Roesky, should be highlighted; this continued harmoniously throughout their careers. Their highly successful combination of problem-solving, structural characterization with original, creative synthesis, was recognized with the Gottfried Wilhelm Leibniz Prize, the highest award of the German Deutsche Forschungsgemeinschaft (DFG), in 1988.

Other awards and honours from the scientific, chemical and crystallographic societies include the following: Meldola and Corday-Morgan (Royal Society of Chemistry), Carl-Hermann (DGK), Patterson (ACA), Perutz (ECA), Ewald (IUCr) and Aminoff (Royal Swedish Academy of Sciences), membership of the Niedersächsische Akademie der Wissenschaften zu Göttingen in 1989, and the crowning glory for the British of being elected a Fellow of the Royal Society. While feeling deeply honoured by the recognition of his peers, George would become embarrassed when being thanked or praised. In 2019, at the ECM in Vienna, during the `Teaching a young dog old tricks' microsymposium, a crystallographer in the audience improvised a concise speech thanking George for the contribution in his programs, which was unanimously backed by a standing ovation. George blushed, but proudly told Katherine about this when they met after the session. Since 2024, the ECA has conferred the Sheldrick Prize to a non-tenured scientist for extraordinary work in the field of structural sciences.

The first major program releases in Göttingen, SHELXS-86, SHELXS-90 and SHELXL-93, greatly extended the power of solution with phase annealing (Sheldrick et al., 1993) and the flexibility of refinement by including a variety of restraints, handling of site substitutions and other well integrated and elegant options to handle complex disorder situations in a versatile and user-friendly way. Introducing refinement based on intensities (rather than structure factors) improved the accuracy of the determinations. SHELXL-97 continued this, extending the scope of the program to handle macromolecular structures at atomic resolution.

Twinning, the frequent phenomenon in crystallography whereby several crystal lattices grow intertwined, was also successfully handled. The complications for structure solution and refinement derived from scattering contributed from different lattices, with total or partial overlap were one of the challenges actively addressed in the laboratory in the development of SHELXL-93. Twinning – if unaccounted for – could lead to erroneous structural determination. Within mineralogy, this and additional solutions to multiple substitution of ions occupying equivalent sites made it possible to overcome significant hurdles. This is exemplified in the naming of a mineral from Mount Saint-Hilaire in Canada to acknowledge the contribution of the SHELX methods. Sheldrickite is a sodium calcium carbonate fluoride mineral, named in honour of George M. Sheldrick to acknowledge that determination of the structure of this mineral required the software's capability of handling twinned crystals; thus, recognition of the help woven in the lives of others was also engraved in stone!

The extension of direct methods to solve the phase problem in more complicated structures of macromolecules (larger and without heavy atoms) was implemented in the second half of the 1990s in George's program SHELXD. This was developed in friendly competition with the Shake and Bake method introduced by the group of Herbert Hauptman, who had been awarded the Nobel Prize in the year 1985 for his work on direct methods. Indeed, both groups worked independently but acknowledged each other's merits with remarkable fairness. George increased the radius of convergence by introducing random omit maps: discarding one third of the atoms in the current solution at random allowed locked solutions to shake off model bias and proceed into completeness. George would make starts consistent with the Patterson function without solving it, in order to preserve enough randomness to avoid repeating starts. Also, along with starts generated from a random set of atoms it was possible to seed solutions from a randomly placed and locally optimized fragment. The success of SHELXD peaked at a conference on direct methods – the famous Erice School – in 1997, during which the structure of the triclinic form of lysozyme was solved. Overcoming the 1000 atom barrier (the structure had 1001 independent atoms) proved the power of SHELXD but the impact of this advance is better reflected in the determination of a number of structures, which had remained unsolved for years until then: numerous antibiotics like mersacidin, several actinomycins, balhimycin… culminating in the solution of vancomycin, for which investigation of a subproduct in Cambridge had allowed George a first glimpse 20 years earlier. Vancomycin was solved in parallel by the Shake and Bake team and published independently within a friendly agreement to tie submission time of the respective manuscripts so as not to harm the other group. This is not unheard of, but George's use of his methods to solve the structure of the pumpkin trypsin inhibitor from competitors during a crystallography school in Poland whereas we were working in Göttingen on the very close squash inhibitor was rather remarkable. Their data were better than ours, he fairly acknowledged returning from this trip. Such plant inhibitors, like the antibiotics; some active peptides like octreotide; peptidic toxins from leeches, cone-snails, scorpions or snakes; large cyclo­dextrins and cyclo­amyloses mimicking starch had waited decades for these methods to unravel their structures from crystals. Some proteins were also solved ab initio: cytochrome c₆, HIPIP, ferredoxin. Later on, poly(A)RNA would be solved at atomic resolution, 50 years after its fibre diffraction structure in Alexander Rich's laboratory.

Extension to macromolecules was most effective in experimental phasing; so much so that the application of the SHELXC–SHELXD–SHELXE pipeline for experimental structure phasing solved too many structures to count or keep track of. Both robust and efficient, they became the standard to calibrate and evaluate performance of synchrotron beamlines.

George Sheldrick should have entered the emeritus status in 2011 but received a Niedersachsenprofessur, allowing him to extend his chair for six further years. This time was also remarkably productive: a last rewrite in SHELXL (Sheldrick, 2015a) allowed him to incorporate features to handle all types of radiation or to read in scattering contributions to address disordered solvent in large supramolecular structures. Unlike previous software, undergoing several cycles of rewriting, SHELXT (Sheldrick, 2015b), his dual-space recycling program integrating structure solution with space group determination and element assignment, was written in one sweep as George knew exactly what he wanted to program and, once written, it all worked according to plan.

In lectures, talks or conversations, George would explain complicated concepts making them come across as compellingly simple. His teaching would always prompt critical thinking, as when he faked a nuclear explosion producing a mushroom cloud in his experimental chemistry lecture. This was the 1980s and half of the audience started an impromptu demonstration against nuclear power before being absorbed in the debate of why this was impossible and the analysis of what experiment had really taken place. In the 21st century George started a well attended course on environmental chemistry with timely, thought-provoking lectures where he would transmit more chemistry than students realized. Many SHELX workshops were organized through the years and enthusiastically attended by students and tutors.

Former students and co-workers would frequently stop in Göttingen and pop by to join the coffee time, where daily group discussions would take place. Many of us have kept in touch ever since, resorted to him for advice, to share news of personal or professional success or just for the pleasure of discussing science and puzzling problems.

Figure 5. Daily meetings and occasional visitors around the coffee table. From left to right: Frank Pauer, Sally Brooker, Thomas Kottke, Ursula Pieper, Kirsten Krahnstöver, Axel Göhrt, Regine Herbst-Irmer, Holger Beck, Erhard Irmer, George Sheldrick.

 

Figure 6. Group in the early 1990s around the Quatermass diffractometer. Back row left to right: Heinz Gornitzka, Dietmar Stalke, Ludger Häming, George M. Sheldrick, Alexander Steiner, Helmut Dehnhardt, Annja Kuhn, Regine Herbst-Irmer, Andreas Heine. Front row: Ehmke Pohl, Miene Schäfer, Ursula Pieper.

 

Figure 7. George and his group at the ACA 2011. Left to right: Birger Dittrich, Christian Hübschle, Peter Müller, Kevin Pröpper, George M. Sheldrick accompanied by Katherine E. Sheldrick.

The lasting legacy for those of us lucky enough to have interacted with George is that of having improved ourselves and our work by it: success for all. The appreciation is further seen in the response to the birthday parties (disguised as Christmas parties) that took place in 2012 and 2017. Also, in the surprise movie his whole group made for him in 2002. The plot followed a student in crystallography from the first steps to becoming big and famous (groß und berühmt), through a large collection of sketches based on true events. For example, there was a blackboard outside George's door where he would write down the details of the next group seminar. On the day where Seminar über Symmetrie im Reziproken Raum was announced, two very stressed new students were asking around where the reciprocal classroom was located. After experiencing that George could unexpectedly walk into the film set even at night or at weekends, the schedule was fixed during the time of his lectures!

George mentioned that the better funding opportunities in Germany at the time were not the main incentive to join the excellent University of Göttingen but that he and Katherine truly appreciated the qualities of the school system for raising their children Abigail, Nicola, Peter and Alexander; he also felt that German academia was more open and comfortably untied by class distinction. Not that George minded too much about nationality but when borders returned to Europe, George and Katherine acquired German citizenship, without becoming less British. Their integration in German society beyond university is seen in Katherine's engagement in music. Their environmental concern motivated the rebuilding of their house, after it burned down in 2008, meticulously designed for energy efficiency with geothermal heat and air recycling, long before climate change became a major topic of public debate.

Acknowledgements

The authors would like to acknowledge help from John Helliwell, Bill Clegg, Larry Falvello, Peter Jones, Peter Müller, Stefanie Freitag-Pohl and Ehmke Pohl. All the thoughts transmitted via the CCP4 bulletin board, Bruker mailing list and other social networks, are also echoed in this text.

References

Beagley, B., Cruickshank, D. W. J., Pinder, P. M., Robiette, A. G. & Sheldrick, G. M. (1969). Acta Cryst. B25, 737–744.

Beagley, B., Robiette, A. G. & Sheldrick, G. M. (1968). J. Chem. Soc. A, pp. 3002.

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

Sheldrick, G. M. (2015a). Acta Cryst. A71, 3–8.

Sheldrick, G. M. (2015b). Acta Cryst. C71, 3–8.

Sheldrick, G. M., Dauter, Z., Wilson, K. S., Hope, H. & Sieker, L. C. (1993). Acta Cryst. D49, 18–23.

Sheldrick, G. M., Jones, P. G., Kennard, O., Williams, D. H. & Smith, G. A. (1978). Nature, 271, 223–225.

Viswamitra, M. A., Kennard, O., Jones, P. G., Sheldrick, G. M., Salisbury, S., Falvello, L. R. & Shakked, Z. (1978). Nature, 273, 687–688.

 

This article was originally published in Acta Cryst. (2025). A81.

The International Science Council (ISC) has issued a letter to its members from President Sir Peter Gluckman and President-elect Professor Robbert Dijkgraaf. The letter provides guidance on the role of the scientific community in responding to global challenges and highlights the importance of scientific collaboration and leadership in times of uncertainty. The full letter is available as a PDF.

The IUCr is a Scientific Union Member of the International Science Council (admitted 1947).

The year 2025 awoke with the double shock of the death of two of our most outstanding colleagues, Sine Larsen and George Sheldrick, both of whom shone and will continue to shine in the universe of crystallography.

Both represent the spectacular advance of science and technology thanks to structural science in the second half of the 20th century. As scientific director of ESRF, Sine Larsen, who left us on 2nd January, represented very well the influence that large synchrotron and neutron facilities have had on structural science. While George Sheldrick was able to evolve his crystallographic system SHELX to provide methodologies and software tools for solving the structure of small molecules and macromolecules, and thus contributed to the development of structural biology. Both had the recognition of the IUCr. Sine, IUCr president in the period 2008-2011, was awarded the ECA Max Perutz Prize in 2018 and George was awarded the Ewald Prize in 2011.

Both were eminent scientists and exceptional human beings, and we can all recount the experiences we have shared with both in the context of the IUCr. We owe them a lot and we miss them already. They have been an example to follow for many of us and will continue to be for several generations of structural scientists.

The Chester team is consolidating its renewal, with Carol Cook's retirement and the incorporation of Harriet Jackson. With the editorial leadership of Louise Jones and Kruna Vukmirovic, and marketing with Kezia Bowman, we have completed the configuration of a team that will give stability to our Chester office for years to come. There is also every indication that our resources will soon recover to pre-pandemic levels.

The third General Assembly of the International Science Council (ISC) attended by Graciela Diaz, produced some interesting discussions on topics of interest to our Union. In particular, Graciela participated in the discussion on 'Transforming science: open science, researcher assessment, science publishing'. The unions produced resolutions on the Ethical Responsibilities of Science in the Context of War and Conflict and one particularly interesting resolution on the free movement of scientists, with a direct appeal to Immigration Officers.

In the year leading up to the Congress in 2026, progress is being made, both in the organisation of our General Assembly and Congress and in the analysis of the situation with our publications and finances. The latter depending to a large extent on the smooth running of our journals, books and International Tables. We need to strive to introduce innovations into our editorial activity in an agile way. This has to go hand in hand with the collaboration between experience and youth, which we are introducing with Early Career Boards and new strategies to expand the community of structural scientists attracted to our journals.

The programme of our next triennial Congress is being organised by the International Programme Committee (IPC), made up of representatives of the Scientific Commissions, coordinated by competent and efficient chairs. The number of proposals for Microsymposia, Keynote and Plenary presentations is very high and will undoubtedly converge in an excellent and attractive programme. The Executive Committee has proposed four cross-cutting Microsymposia that will allow us to discuss key aspects of the future of our Union, the future of our Journals, the impact of our Commissions on global science and the future of the community of structural scientists.

In March, the annual meeting of the Journals Management Board noted the recovery of our publications towards 2019 levels, and included a lecture by Kate McKellar (Wiley). Although we missed Peter Strickland, the organization of the new technical officers, Kruna Vukmirovic, Head of Publishing Strategy, and Louise Jones, Head of Publishing Operations, was impeccable. As well as updates on each of the journals, the implementation of the Early Career Boards and the introduction of more streamlined procedures for publishing special issues were discussed.

Following the journals meeting, the Finance Committee met in Lund at the LINKS premises at the invitation of the General Secretary and Treasurer, Trevor Forsyth. Time was spent examining the recovery of our finances, making decisions on the future of our investments, the Meetings Support Committee and Outreach Committee funds, and reviewing the status of our publications and the triennial Congress, which are our main sources of funds. The Finance Committee will meet again in August in Poznan to coincide with ECM25.

As usual, I end this letter with deep gratitude to all those who form and make our organisation work: the Regional Associates, the IUCr Commissions and Committees, Editors, Co-editors, referees and authors of our journals, our Chester staff and all individual structural scientists, women and men.

Thanks to IUCr Newsletter Editor Mike Glazer, and his team, and thanks to all contributors for making possible, as with every issue, a new issue that continues to be the reference communication for our community.

Thank you all for helping to keep the momentum of the IUCr going, wherever you are in the world.

Last May, 26th–31st, the 18th International Symposium on Metal-Hydrogen Systems – MH2024 took place at Saint Malo (France), co-organized by Université Catholique de Louvain (Belgium) and CNRS/UPEC Institut de Chimie et des Matériaux Paris-Est (France). It brought together 416 researchers, both from academia and industry, coming from 5 continents and 36 countries. The conference scope was the fundamentals and development of new material-hydrogen systems, with expected applications, among others, in hydrogen storage, compression, purification, transport and sensing, as well as in electrochemical devices.

The MH2024 scientific program included 5 plenary sessions, 33 invited lectures, 165 oral presentations and more than 180 posters. Major results on chemistry, metallurgy and research on metal-hydrogen technologies were awarded by 13 prizes, including the prestigious MH2024 best poster award prize in Chemistry from the American Chemical Society. Original scientific papers will be published in a special issue of ACS-Applied Energy Materials after a standard peer reviewing process.

The inspiring presentations and in-depth discussions that took place during MH2024 witnessed new exciting scientific discoveries in the field of hydride-based materials, contributing to progress towards the energy transition.

The IUCr generously provided financial support of $4000, covering full or partial registration fees for 11 researchers from France, Argentina and Switzerland. This support benefited 10 PhD students and a retired professor of crystallography, enhancing the meeting’s engagement and showcasing the vital role of crystallography in material science.

During the summer of 2024, representatives of the European Crystallographic Association (ECA) invited me to summarize, in a short video [1], some history published in 2004 [2] and 2015 [3]. The video (Fig. 1) was part of a series, "Women in Crystallography", supported by the Royal Society of Chemistry Inclusion and Diversity Fund. As written in a previous issue of the IUCr Newsletter by the organizers, the video project intends "to celebrate the importance of women in the field of crystallography and science while raising awareness about the pitfalls and obstacles on the way to reach gender parity in science..." [4].

Figure 1. Opening frame. Women in Crystallography #5. Produced by the European Crystallographic Association [1].

Since then, in the United States, considerations of diversity, equity and inclusion (DEI) in science, education and the workplace, once welcomed by the government, have been reframed, foremost in executive orders (nos. 14151 and 14173) in January 2025 - "Ending Radical and Wasteful Government DEI Programs and Preferences" and "Ending Illegal Discrimination and Restoring Merit-Based Opportunity" [5]. However, the US National Science Foundation (NSF) supported the research that informed the video production under its Broader Impacts mission. For more than three decades, the NSF has doggedly forged a scientific workforce that more closely represents our multi-gendered multicultural American society by enlarging the concept of merit. In the sincerity and tenacity of this ongoing effort, the NSF has transformed the national academic science community. These NSF values on which I was raised as a scientist are well aligned with those of the ECA. However, this alignment will undoubtedly require increasing chiropractic care as the United States dismisses common interests with other nations and broadcasts its new policies that label concerns about representation as misguided and disqualifying.

Long before this new dark age, as I was preparing to attend university, my older brother announced that he would go first and study psychology. "A fool's mission", I declared, "People are too complicated. I will study crystals", I predicted with satisfaction. We did as we said. Now, decades later, it seems obvious to me that our greatest problems as a community will not be solved with crystals if we don't first understand more about human behavior. Perovskite solar cells must be directed at the sun…by people. Despite raising a thousand generations of babies since neolithic times, we cannot eschew the individuals among us who may affect, directly and adversely, millions.

The video requested by the ECA was an effort to explain something about people, still too complicated but perhaps not hopelessly so.

It has been observed frequently that women were atypically well populated in one area of physical science in the last century - the study of crystal structure with X-rays (see e.g. [6]). Dorothy Hodgkin (1910-1994), Kathleen Lonsdale (1903-1971), Dorothy Wrinch (1894-1976), Elizabeth Wood (1912-2006), Helen Megaw (1907-1922) and Rosalind Franklin (1920-1958), stand out, among others. Since this group was such a bright spot in an otherwise male-centric history of physical science, it invited explanations. But, because of a lack of understanding of psychology, these purported explanations have tended to be pejorative. Some have said that crystallography was a helpmate to chemistry, physics, biology and geology, just like wives were traditionally helpmates to husbands. Some have said that summing terms in a Fourier series prior to electronic computers was tedious, like knitting, and well adapted to the female mind. These cavalier "explanations" were collected in [2].

However, there came into my focus a credible evidence-based understanding of this gender anomaly. It came into my focus only because I was engaged in the business of raising one of those post-neolithic babies. Only after sending a child to kindergarten did I learn what kindergarten had been all about at the time of its inception. Moreover, the foundational principles of kindergarten, improbably, impacted the early educational experiences of the pioneering X-ray crystallographers, a story that I was asked to tell by members of the ECA, using the medium of film actualized by the aforementioned kindergartener, now a grown-up filmmaker. After our contribution to the ECA project was completed, the IUCr Newsletter Editor invited me to reduce the film to this article. So, here is a story about inclusivity, told with the confidence that these stories remain valuable.

Crystallography, it turns out, had a tremendous influence on early childhood education in the 19th century generally. We became aware of this through the work of two scholars: Jeanne Rubin, a music professor at Kent State University [7] and Norman Brosterman, an architect and historian [8]. They told the story of Friederich Fröbel (1782-1852) (scholarship on the influence of crystallography on kindergarten continues, in particular by examination of Fröbel’s notebooks held in the Fröbel museum in Bad Blankenburg, see e.g. [9a, 9b]).

Fröbel was born in the Thuringian forest of Prussia. He was largely self-educated but took some natural science classes in Jena and Göttingen, interrupted by a stay in a debtor's prison and his voluntary service battling Napoleon's army. Afterward, somehow, he became an assistant to Christian Samuel Weiss (1780-1856) at the Mineralogy Museum in Berlin. Weiss invented the concept of the crystallographic system. Fröbel must have been a favored apprentice because, in 1817, he was offered a professorship in mineralogy in Stockholm. He reluctantly turned it down.

Fröbel, a 19th-century romantic, believed children and crystals grow according to the same natural laws. However, he thought children were too complicated to study, a fool's mission. On the other hand, in the 19th century, crystals were merely polyhedra that could be described with geometry. Fröbel thus believed that the surest path for children to the mind of God was the study of crystals and their symmetries. Fröbel explained how this notion caused him to depart from his career plans in higher education. He said [reduced for concision]:

"It had long been my dearest wish to devote myself to an academic career, for I thought to find in it my vocation, the meaning of my life. But the opportunity to get to know students and … their lack of any true scientific spirit made me go back on my purpose ... Meanwhile, the stones in my hand and under my eyes became forms of life that spoke a language I understood. The world of crystals clearly proclaimed the structure of life to me" [10,11].

Fröbel devoted the rest of his life to developing a system of early childhood education. In Prussia, in the early 19th century, schooling typically began at age 7. To seize on lost opportunity, Fröbel's invented kindergarten [8] for younger children with a highly circumscribed pedagogy. The Fröbel kindergarten curriculum was based on 20 so-called Gifts and Occupations. Each were lattice, tessellation or polyhedron-building exercises of one kind or another so that children could mimic crystals with a dual educational and spiritual purpose. The "polymorphism" arising from the decoration of "special positions" with tiles or blocks having the same symmetry as the ensemble was a staple of Fröbel's training, often on gridded tabletops (Fig. 2, [12,13]). Stepwise instructions for the transformation of these iso-symmetric forms are given in a recent book by Rogers [14].

Figure 2. Activities with 9 equilateral triangular tiles (left) and 8 cubic blocks (right) from manuals for kindergarten teachers, [11] and [12], respectively.

Following the pro-democracy rebellions that rocked Europe in 1848, the Prussian monarchy decided it was safer if the people remained undereducated. Kindergarten was outlawed, and Fröbel died heartbroken. But, by this time, talented women had taken to teaching kindergarten as a vocation, and Fröbel's invention spread quickly internationally [15]. However, its crystallographic content was diminished by successive generations because new kindergarten teachers were not trained as mineralogists.

Jeanne Rubin lived in a house designed by the pioneering American architect Frank Lloyd Wright (1867-1959), and that is how her book Intimate Triangle [7] joins Wright to the two mineralogists Weiss and Fröbel on its cover (Fig. 3). Wright's mother, Anna, was a Fröbel kindergarten teacher in Wisconsin, and Wright wrote in his autobiographies [16a, 16b] about how important old Fröbel's philosophy was to his development as an architect.

However, Rubin and Brosterman show through their scholarship and the unusual hobby of Brosterman - collecting vintage kindergarten art - that the influence of Fröbel kindergartens extended well beyond Wright. Legions of children in the half-century preceding World War I were exposed to Fröbel's methodology. Rubin and Brosterman persuasively argue that the Fröbel system of training children to work with the geometries and symmetries of crystals was a force that led to modernism in the visual arts and architecture brought forward by Fröbel kindergarten graduates. Besides Wright, Le Corbusier (1887-1965), Paul Klee (1979-1940), Walter Gropius (1883-1969), Josef Albers, Wassily Kandinsky (1888-1976) and Georges Braque (1882-1963), among other pioneers, likely attended Fröbel or Fröbel-inspired kindergartens. Brosterman's comparisons [8] of turn-of-the-century American kindergarten art with paintings by famous artists make a compelling case for a Fröbel-catalyzed rebellion against convention in Western art and architecture.

In reviewing this history, we articulated a natural corollary:

"If many of the pioneering artists had their geometric sensibilities inculcated in Fröbel kindergartens, it is likely that pioneering X-ray crystallographers had a similar experience. Did the crystallographic content of late nineteenth-century kindergarten play a role in the explosion of research into the architecture of crystals? In other words, did the crystallographic content of kindergarten influence the future development of crystallography?" [2].

Such an investigation would require a collection of early childhood biographies of the pioneers of X-ray crystallography. A place to start would be with the women especially. Is it possible that many girls were exposed to crystallography in kindergarten before being systemically shut out of the study of the natural sciences by conventional schooling biases?

Our friend Jeanne Rubin took up this suggestion. She wrote by email in 2006 [17]: "On your question about the burgeoning number of female crystallographers early in the last century, I've already tracked down documentation of the Fröbel training of Rosalind Franklin and am working on others." However, the next year, Jeanne passed away at the age of 90.

Years later, in 2015, there was an invitation to contribute to a special issue of the American Chemical Society journal Crystal Growth and Design organized in memory of the widely admired crystallographer Peggy Etter (1943-1992) of the University of Minnesota. For this initiative, we thought that we should try to finish the inquiry that Rubin started. Much had changed since 2006. The adolescent internet had grown up. While it would have been impossible to unearth the philosophies of the educational experiences of the pioneering female X-ray crystallographers in the early years of the 20th century, the web had spread quickly and we could follow its tendrils.

Rosalind Franklin's first school was Norland Place, founded by Emily Lord (1850-1930) to spread Fröbel's philosophy to kids aged 3-8. Lord founded Britain's Fröbel society. Dorothy Hodgkin attended the Parents National Educational Union founded by Charlotte Mason (1842-1923), a Fröbel disciple who said "We reverence Friederich Fröbel. We share many of his great thoughts.” According to Hodgkin, "[The school] produced small books to introduce their pupils to the different sciences. The book on chemistry began with growing crystals of copper sulfate and alum. I found this fascinating and repeated the experiments at home." Elizabeth Wood attended the Horace Mann School, an experimental high school of Columbia University's Teacher's College. The Teacher's College Record put out a stream of articles on the virtues of Fröbel schooling from 1900 onwards. Horace Mann (1796-1859) was the brother-in-law of Elizabeth Peabody (1808-1894), for whom the Fröbel kindergarten "was not simply a method of education but a movement of mystical significance. Her advocacy was an 'apostolate', kindergartening a religion, a 'Gospel for children'." Mary Peabody Mann (1806-1887), the wife of Horace, translated [15] from German to English. Mary called the Fröbel kindergarten "the free republic of childhood" [15, p. ix]. Helen Megaw attended the Alexandra School in Dublin that cites a "philosophy of teaching and learning [that] is child-centered and based on the principles of Friedrich Fröbel". The Alexandra School worked with the Fröbel College in Sion Hill to extend Fröbel pedagogy to the lower classes. Later, she attended Roedean School in Brighton, founded by Penelope Lawrence (1856-1932). Lawrence was the principal of the Fröbel Society's Kindergarten Training College in London. Kathleen Lonsdale attended the Bedford Training College, which prepared students for National Fröbel Union Examinations. Dorothy Wrinch's sister Muriel earned a Fröbel certificate. She attended Girton College in Cambridge, where her headmistress was Emily Shirreff (1814-1897), founder of the Fröbel Society in 1876. (The citations that support each attribution and quotation in this paragraph can be found in [3].)

The United States aspires to strengthen its scientific workforce by ensuring that it more closely reflects the genders and ethnicities of the American population. Activities that support this democratic goal are said to have "Broader Impacts" because they align science and engineering with societal goals. But, societal goals seem to be changing, rapidly. The NSF's Broader Impacts landing page at present [18], by happenstance, has a banner that features some crystals grown in our laboratory. Creating a "diverse" workforce remains one of the ways advertised to satisfy the Broader Impacts mission, even while webpages (.gov) of federal agencies in the USA are being scrubbed (last examined 29 March 2025).

Psychologists and sociologists have considered the importance of representation, and we should know what they have learned ([19], see examples and references therein). Sustained achievement in a field filled with obstacles, both intrinsic to the discipline and extrinsic from prejudicial expectations of others, requires identification with the discipline. The cultivation of an identity associated with science is the counterweight to stereotype threats, malicious or otherwise. People will fight to maintain their identities, even when the going gets tough. Where better than kindergarten to forge an identity with science and mathematics that can serve to counteract the negative consequence of prejudice? This is what Friederich Fröbel achieved through kindergarten.

Naturally, if the Fröbel kindergarten had influenced girls, it would have also worked on boys. For instance, we don't know much about the early life of the idiosyncratic William Barlow (1845-1934), a pre-X-ray pioneer in crystal structure and space group prediction [20]. Barlow, an heir to a sizeable estate, didn't need or receive a systematic education, but he approached crystals systematically. Was he imprinted by a crystallographic system at a formidable age? Barlow turned 6 when Johannes (1813-1887) and Bertha Ronge (1818-1863) brought the first Fröbel kindergarten to Britain [13]. Their school was sited in central London, where Barlow was born and raised. Are there identifiable reasons for the devotion of Barlow, among others, to the internal structure of crystals? We haven't collected the necessary biographical facts, and boys may have been encouraged by more obvious mechanisms. Crystallography may also have been welcoming to young women because of the egalitarian impulses of William Henry Bragg, William Lawrence Bragg and John Desmond Bernal. There won't be a universal explanation.

Did X-ray crystallography receive a special boost in female contributions because of the crystallographic pedagogy of the Fröbel kindergarten? Perhaps. But establishing causality in history is hard. In crystallography, we like statistics. But lack of certainty is preferable to silly comparisons of X-ray analysis to knitting. Meanwhile, check out the other ECA videos in the series here.

References

[1] European Crystallographic Association (2025). Fifth video of the “Women in Crystallography” series, https://ecanews.org/blog/2025/03/07/fifth-video-of-the-women-in-crystallography-series/.

[2] Kahr, B. (2004). Crystal engineering in kindergarten. Cryst. Growth Des. 4, 3–9.

[3] Kahr, B. (2015). Broader impacts of women in crystallography. Cryst. Growth Des. 15, 4715–4730.

[4] Women in Crystallography project (2024). IUCr Newsletter, 32, https://www.iucr.org/news/newsletter/volume-32/number-2/women-in-crystallography-project.

[5] National Archives (2025). Executive Orders, https://www.federalregister.gov/presidential-documents/executive-orders/.

[6] Aparicio, J. S. (2015). The legacy of women to crystallography, Arbor, 191, a216.

[7] Rubin, J. S. (2002). Intimate triangle: architecture of crystals, Frank Lloyd Wright and the Froebel kindergarten. Huntsville, Alabama: Polycrystal Book Service.

[8] Brosterman, N. (1997). Inventing kindergarten. New York: Harry N. Abrams.

[9a] Friedman, M. & Muñoz Alvis, J. (2023). Haüy, Weiß, Fröbel: the influence of nineteenth-century crystallography on the mathematics of Friedrich Fröbel's kindergarten. Part 1: the published materials. Paedagog. Hist. 59, 191–211.

[9b] Friedman, M. & Muñoz Alvis, J. (2023). Haüy, Weiß, Fröbel: the influence of nineteenth-century crystallography on the mathematics of Friedrich Fröbel's kindergarten. Part 2: new evidence from unpublished notes. Paedagog. Hist. 59, 212–232.

[10] Froebel, F. (1967). Letter to Karl Christoph Friederich Krause, 1828. Friederich Froebel: a selection from his writings, edited by I. M. Lilley, p. 39. Cambridge University Press.

[11] Froebel, F. (1906). Autobiography of Friederich Froebel, p. 112. London: Swan Sonnenschein & Co.

[12] Wiebé, E. (1910). Golden jubilee edition of the paradise of childhood. Springfield: Milton Bradley.

[13] Ronge, J. & Ronge, B. (1858). Practical guide to English kindergarten, 2nd ed. London: Hodson and Son.

[14] Rogers, W. (2016). Close-up view of Froebel's kindergarten with Frank Lloyd Wright at the drawing table. Xlibris.

[15] von Marenholtz-Bülow, B. (2007). How kindergarten came to America. New York: The New Press. [Originally published in 1895 as The reminiscences of Friederich Froebel. Boston: Lee and Shepard.]

[16a] Wright, F. L. (1943). An Autobiography, pp. 13-14. New York: Duell, Sloan and Pearce.

[16b] Wright, F. L. (1957). A Testament, pp. 19-21, 63, 100, 206-207, 220. New York: Bramhall House.

[17] Rubin, J. (2006). Email to B. Kahr, 10 April.

[18] National Science Foundation (2025). Broader impacts, https://www.nsf.gov/funding/learn/broader-impacts.

[19] Steele, C. M. (2011). Whistling Vivaldi. New York: W. W. Norton.

[20] Tandy, P. (2004). William Barlow (1845–1934): speculative builder, man of leisure and inspired crystallographer. Proc. Geol. Assoc. 115, 77–84.

We are excited to launch CSD-Frameworks, the new suite to accelerate the development of metal-organic frameworks (MOFs) and other porous materials. Using trusted experimental and curated data from the CSD, CSD-Frameworks will guide research, optimize materials design, and offer deeper insights into porous materials.

CSD-Frameworks provides:

• Crystal structure visualization and analysis.
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• Pore and void characterization.
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• Solvate and guest molecule analysis.
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• Chemical and structural searches.
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• Access to the entire CSD, including a curated collection of 100,000+ MOF structures.

Learn more about CSD-Frameworks in the new white paper.

Blog: The CCDC and Durham University Awarded an Innovate UK Grant to Advance Sustainable Medicines Manufacturing through Digital Particle Engineering

The CCDC and Durham University have received an Innovate UK grant for the "Sustainable Medicines Manufacturing: Collaborative R&D" initiative. This funding will allow for the integration of the ADDICT prototype software into our CSD-Particle suite within the Mercury platform, promoting digitalization in pharmaceutical manufacturing and supporting the industry's transition towards sustainable practices.

Over half (10,350) of the new structures in the CSD are metal-organic structures that can be classified as coordination complexes and MOFs. Among them, there is an example of cobalt(II) spin-state isomers that can be physically separated, as reported by Wheaton et al. (2024). This discovery reveals how subtle coordination geometry and solvent polarity changes can control spin states.

This webinar introduces CSD-Frameworks. As mentioned above, CSD-Frameworks is a new software suite from the CCDC designed to enhance research on MOFs and porous materials. It utilizes a curated database with over 120,000 experimentally determined structures to facilitate materials design and analysis. This webinar will feature live demonstrations of key functionalities, including pore and void characterization, guest molecule analysis, and chemical searches.

Register here

How To Video: Explore Molecules and Create Eye-Catching Graphics with Mercury 

Learn how to use Mercury's core features to explore molecules and crystal structures. This video shows you how to select CSD structures, choose display styles, analyze intermolecular interactions, measure distances and angles, and create high-quality images for reports and presentations. Watch now!

References

Wheaton, A. M., Chipman, J. A., Walde, R. K., Hofstetter, H. & Berry, J. F. (2024). J. Am. Chem. Soc. 146, 26926–26935.

The Gjønnes Medal in Electron Crystallography is awarded every three years and recognizes an outstanding contribution to the field of electron crystallography. The Gjønnes Medal is accompanied by a certificate and funding to present an invited Keynote Lecture at the triennial International Congress of Crystallography.

Administration

This award is managed by the Awards Sub-committee of the Commission on Electron Crystallography (CEC) of the IUCr. This Sub-committee is responsible for soliciting and evaluating and recommending a nominee to members of the CEC for final approval, or recommending that no award be made.

Rules and eligibility

Nomination for the Gjønnes Medal is open to scientists and engineers in all areas of electron crystallography, defined in the broadest context as the branch of science that uses electron scattering and imaging to study the structure of matter. Nominees of any nationality are eligible. It is expected that the nomination will be for a single person. However, since breakthrough innovations often involve more than one individual, the nomination can be for two or three people maximum. In the case of multiple nominees, it must be shown that each person contributed roughly equally to the innovation.

The Award will not be bestowed in absentia, except in extraordinary circumstances. Current members of the CEC, members of the IUCr Executive Committee and previous recipients of the Gjønnes Medal are not eligible.

Nomination procedure

Nominations are invited for the next Gjønnes Medal, which will be awarded at the IUCr Congress in Calgary, Canada, in August 2026.

The nomination packet should be sent to the Chair of the CEC, Dr Mauro Gemmi (mauro.gemmi@iit.it), and should include the following:

• A letter of no more than 3000 characters evaluating the nominee's qualifications in the field of electron crystallography and identifying the specific work to be recognized. There is no nomination form, so this letter is considered the nomination 'application'.
• Curriculum vitae of the nominee.
• A list of the most important publications of the nominee.
• At least two, but no more than four, seconding letters.

The deadline for receipt of nominations is 31 August 2025.

Previous recipients

Previous recipients included Professor Jian-Min Zuo, who received the 2023 Gjønnes Medal for his outstanding contributions to the development and application of quantitative electron diffraction at the 25th IUCr Congress in Melbourne, Australia.

In 2017, the Nobel Prize winner Richard Henderson, along with Nigel Unwin, received the Gjønnes Medal at the 24th IUCr Congress in Hyderabad, India, for the development and powerful application of structural determination methods for biological complexes at near-atomic resolution using electron crystallography. In 2014, John Steeds and Michiyoshi Tanaka were awarded the medal for their outstanding contributions to convergent-beam electron diffraction, and the 2011 awardees were Archie Howie and Michael Whelan for the development of the dynamical theory of diffraction contrast of electron microscope images of defects in crystals, and other major pioneering contributions to the development and application of electron microscopy, diffraction and spectroscopy of materials.

The medal is named in honour of its first recipient, Jon Gjønnes, who received the award at the 21st IUCr Congress in Osaka, Japan, in 2008. He said: “The basic scientific achievements of the last century - which one may epitomise by three words: the atom, the computer and the gene - rest on two main efforts: Quantum theory - which is prerequisite to our understanding of the atoms and the way they are put together - and Crystallography - which is the basic never-ending task of exploring the atomic architecture of matter".