Schedule

Keynote

Structural Chemistry
Keynote

High Pressure
Keynote

Co-Chairs: Wei Dai & Genji Kurisu Sponsoring Commission: Biological Macromolecules CryoEM has yet to reach its full potential as predicted by theoretical considerations. Detectors and other components of the instruments can still be improved to enable the full potential of the technique. This microsymposium will gather leaders in the field who are working to build instruments capable of higher resolution, higher throughput, and broader accessibility. Topics may include stages, continuous tilting, detectors for fast tomography, laser phase plates, fast objective lens current modulation, FIB milling, pulsed laser devitrification, affordable low-voltage cryoEM, cryo holography, 4D STEM, and ptychography.

Biological Macromolecules

Co-Chairs: Isabel Uson & Garib Murshudov Sponsoring Commission: Biological Macromolecules This microsymposium will cover the latest innovations in algorithms and computational methods in crystallography, including advances in model-building software, automation strategies, and best practices for interpreting density maps. It will also address structure solution and refinement techniques for challenging datasets, such as low-resolution diffraction, poorly ordered crystals, and flexible macromolecular complexes. In addition, the session will highlight emerging approaches that integrate machine learning, hybrid modeling, and cross-validation strategies to improve accuracy and reliability, illustrating how computational innovation is transforming modern crystallographic practice.

Biological Macromolecules

Co-Chairs: Mariya Zhuravleva & Philippe Veber Sponsoring Commission: Crystal Growth and Characterization of Materials This microsymposium will highlight recent advances in the growth and development of optical crystals for medical applications. Contributions are expected on novel scintillator crystals for medical imaging techniques, including computed tomography (CT), positron emission tomography (PET), positron emission mammography (PEM), and single-photon emission computed tomography (SPECT), as well as on laser crystals for surgical devices. The session will showcase new materials, growth methods, and characterization strategies, emphasizing which of the latest developments hold the greatest promise for future medical applications.

Crystal Growth and Characterization of Materials

Co-Chairs: Dr. Anna Makal & Prof. Eiji Nishibori Sponsoring Commission: Quantum Crystallography Co-Sponsoring Commission: Magnetic Structures Real materials are neither perfect crystals nor “ideally imperfect” crystals. They are affected by temperature and pressure and contain defects and nanostructures, all of which influence their properties. This microsymposium welcomes contributions on high-pressure crystallography, disordered materials, lattice dynamics, diffuse scattering, interrogation of defects and nanostructures, and the crystallography of excited states, as well as studies of other systems that differ from single-phase, ideal crystals. Such investigations push quantum crystallography toward the measurement of bonding, spin, and momentum densities in unconventional but truly “real” material systems.

Magnetic Structures
Quantum Crystallography

Co-Chairs: Armin Hoell & Volker Urban Sponsoring Commission: Small Angle Scattering Co-Sponsoring Commission: Neutron Scattering This microsymposium will focus on contrast variation methods in small-angle scattering using X-rays, neutrons, or both to analyze complex multicomponent nanostructures in scientific and technical applications. It will address the disentanglement of complex problems in chemistry, physics, biology, materials science, and catalyst research, including critical phenomena, kinetics of phase transitions, self-assembly, transport phenomena, and catalytic activity. The session will also cover theoretical and methodological aspects and the complementary use of neutrons and X-rays in small-angle scattering.

Neutron Scattering
Small-Angle Scattering

Co-Chairs: Irene Diaz-Moreno & Kajsa Sigfridsson Clauss Sponsoring Commission: XAFS Co-Sponsoring Commission: Biological Macromolecules X-ray absorption spectroscopy (XAS) has traditionally been used to determine the local geometrical environment and electronic structure of metal-containing biological systems such as proteins and enzymes. This knowledge, complementary to information obtained with other structural techniques such as crystallography, has been essential for understanding the function of these systems. In recent years, photon-in/photon-out techniques such as resonant and non-resonant X-ray emission spectroscopies (RXES and XES), as well as high-energy-resolution fluorescence-detected XAS (HERFD-XAS), have expanded the X-ray spectroscopy toolkit for investigating chemically specific electronic and geometrical structures. These techniques have been applied to biologically relevant processes, such as small-molecule binding and activation in different ligand protonation states, or the identification of bridging oxo groups in the Mn₄Ca cluster of photosystem II. This microsymposium will bring together experts to provide an overview of novel developments in X-ray spectroscopy that are offering unprecedented insights into biological systems.

Biological Macromolecules
XAFS

Co-Chairs: Alejandro Ayala & Vojtech Jancik Sponsoring Commission: Structural Chemistry This microsymposium will cover the topic of service crystallography, focusing on specialized facilities that provide expert X-ray crystallographic analysis to academic and industrial researchers. Presentations will detail the operational aspects of these core facilities, including sample handling, data collection, and structure determination for a diverse user base. The session will also examine the application of this service model in key scientific areas such as drug discovery, chemical synthesis, and materials science.

Structural Chemistry

Co-Chairs: Martin Lutz & Greg McColm Sponsoring Commission: Crystallographic Computing Graph sets (Etter) and topological indices (Wells) have a long history in the description of organic and inorganic structures, especially crystal structures. At times, their predictive power has been questioned, but the situation has fundamentally changed with the advent of machine learning, which is highly compatible with these descriptors. This microsymposium will showcase the latest applications and provide a platform for presenting needed algorithms, such as the Euler characteristic.

Crystallographic Computing

Co-Chairs: Guilherme Calligaris & Reinhard B. Neder Sponsoring Commission: High Pressure Diffuse scattering is a pivotal technique for investigating local disorder and correlations across diverse disciplines. In quantum materials, it elucidates symmetry breaking and electronic correlations essential for superconductors and functional oxides. In structural chemistry, it offers insights into vacancy networks and dynamic disorder in hybrid materials. In biology, it advances the understanding of correlated motions in proteins and enzyme mechanisms. The application of three-dimensional pair distribution function (3D-PDF) analysis and its variations has expanded the study of single-crystal diffuse scattering, enabling precise characterization of complex disorder and local correlations. This microsymposium will highlight the latest advancements in this field and assess its potential future applications, including compatibility with non-ambient conditions (such as high pressure and low temperature) and its interdisciplinary nature.

High Pressure

Co-Chairs: Hanna Dabkowska & Santiago Garcia-Granda Sponsoring Commission: IUCr Early Career Scientist Division The IUCr Executive Committee initiated a process of reflection to redefine the Purpose, Vision, and Values that characterize the Union and shape its strategies and image as a global scientific organization. This process, launched at the 26th Congress and General Assembly in Melbourne at the initiative of Professor Jenny Martin, has since been adopted by the IUCr, with initial results enabling the redefinition of its identity through the involvement of the entire community of structural scientists. This session will present the community’s contributions to this process and discuss the directions the Union should take in consolidating its position as a representative of structural science in both academic and social contexts. Topics will include sustaining the impact of outreach and education programs to ensure engagement of future generations, responding to challenges of diversity and inclusion, addressing sustainability, and ensuring structural science contributes to societal needs with equity, honesty, truth, and scientific rigor. Key issues, risks, opportunities, and needs for the future of the Union will be discussed, with particular focus on generational renewal, attracting young scientists, and ensuring financial sustainability. The entire structural science community is encouraged to submit ideas.

IUCr Early Career Scientist Division

Organizers: Santosh Panjikar & Martin Lutz The Software Fayre at the 27th IUCr Congress (Calgary, August 11-18, 2026) offers a forum for developers to present new crystallographic software and demonstrate their features through hands-on tutorials. The Fayre will be held August 12-18, with time slots available for registration.

Crystallographic Computing

Co-Chairs: Shaker Chuck Farah & M. Joanne Lemieux Sponsoring Commission: Biological Macromolecules Membrane proteins play a crucial role in numerous biological processes and are increasingly recognized as important therapeutic targets for drug discovery and development. However, their structural characterization presents unique challenges due to their hydrophobic nature, complex dynamics, and the difficulty in obtaining sufficient quantities of functional proteins. This microsymposium will explore the latest advances and methodologies in the structural determination of membrane proteins, including advanced detergent formulations for stabilization and purification, high-throughput crystallization, and cryo-EM. It will provide a platform for sharing knowledge, experiences, and strategies to advance membrane protein research, uncover new biology, and support drug discovery.

Biological Macromolecules

Co-Chairs: Bruce Gaulin & Sylvain Petit Sponsoring Commission: Magnetic Structures Co-Sponsoring Commission: Neutron Scattering

Magnetic Structures
Neutron Scattering

Co-Chairs: Igor Levin Sponsoring Commission: Crystallography of Materials Co-Sponsoring Commission: Synchrotron and XFEL Radiation Supporting Commission: Powder Diffraction Emphasizing the synergy between pair distribution function (PDF) analysis, total scattering, and various spectroscopic techniques, this microsymposium will highlight recent advancements in probing local crystal structure, magnetic structure, and structural dynamics of powder and ceramic materials, and their relationship to bulk material properties.

Crystallography of Materials
Powder Diffraction
Synchrotron and XFEL Radiation

Co-Chairs: Leonard J Mueller & Jill Chrencik Sponsoring Commission: NMR Crystallography and Related Methods Co-Sponsoring Commission: Biological Macromolecules This microsymposium will explore how diverse experimental and computational techniques such as X-ray crystallography, cryo-EM, NMR, and small-angle scattering can be integrated to determine macromolecular structures. It will highlight recent developments in solving structures of different classes of biomolecules, including proteins, nucleic acids, and carbohydrates. Advances in solid-state NMR spectroscopy have enabled new insights into the structure, dynamics, and interactions of biomolecules, providing information complementary to that obtained by other methods. Recent applications emphasize the complementarity of solid-state NMR with other structural biology techniques, such as cryo-EM, solution-state NMR, and X-ray crystallography. Contributions may focus on best practices for combining data from different sources and resolving discrepancies, as well as case studies highlighting successful applications that integrate structural and dynamic information across a variety of time and length scales.

Biological Macromolecules
NMR Crystallography and Related Methods

Co-Chairs: Nathaniel (Nate) Barker & Fabia Gozzo Sponsoring Commission: Crystallographic Teaching Crystallography is vital across disciplines, yet the economics of sustaining laboratories differ greatly between academia and industry. Academic facilities depend on public funding and training mandates, while industry faces strict timelines, regulatory demands, and cost-effectiveness pressures. This microsymposium will examine how funding models, service priorities, and collaboration frameworks shape access, innovation, and long-term sustainability. By contrasting academic and industrial perspectives, it will highlight both challenges and opportunities in building economically viable crystallography services.

Crystallographic Teaching

Co-Chairs: Oliver Hammond & Chiara Maurizio Sponsoring Commission: XAFS Supporting Commission: Powder Diffraction The two archetypal classes of disordered materials are liquids and glasses. Liquids have no long-range order but display local correlations between molecules. Similarly, amorphous solids and glasses are not crystalline materials, i.e., they are solids without long-range order but still exhibit local order between atoms. The short-range sensitivity of XAS makes it ideal for studying disordered materials, while in total neutron scattering analysis the weak diffuse features are related to short- and medium-range order. This microsymposium will highlight the strengths and limitations, as well as the complementarity, of spectroscopic and scattering techniques for understanding the structural correlations at the atomic and molecular scale that underpin the macroscopic properties of disordered materials.

Powder Diffraction
XAFS

Co-Chairs: Adam A. L. Michalchuk & Ivan Halasz Sponsoring Commission: Structural Chemistry This microsymposium will discuss recent progress in understanding mechanochemical transformations in light of crystallographic characterization. It will highlight advancements in the crystallographic analysis of mechanochemical processes, including in situ monitoring and structural characterization of reaction intermediates and products. Key topics will include the role of crystal structure in determining reaction pathways, the development of new mechanochemical methodologies, and the applications of these techniques across disciplines ranging from materials science to pharmaceutical science.

Structural Chemistry

Sponsoring Commission: Crystallographic Computing Co-Chairs: Ella Schmidt & Graham King In experimental sciences, each observation is accompanied by a standard deviation or uncertainty, representing the reliability of the measurement. Experimental design aims to minimize these uncertainties. In diffraction experiments on crystals, a number of methods and algorithms are accepted for determining the uncertainties in the intensities of Bragg reflections. The analysis of diffuse scattering is more recent, and methods and algorithms still need to be established. This microsymposium will provide an opportunity to exchange ideas about experimental design and error analysis.

Crystallographic Computing

Co-Chairs: Abraham Levitan & Pierre Thibault Sponsoring Commission: Synchrotron and XFEL Radiation X-ray ptychography is the highest-resolution X-ray microscopy technique available, capable of achieving spatial resolution below 5 nm under ideal conditions. It leverages the properties of coherent light to achieve resolution not limited by the numerical aperture of an optic but rather by the available coherent flux. Because of this, it is particularly well suited for next-generation diffraction-limited storage rings, which promise dramatic increases in coherence. This microsymposium will highlight the latest advances in X-ray ptychography, including developments in instrumentation, data acquisition strategies, and reconstruction algorithms. Particular focus will be given to lessons learned from recent synchrotron upgrades at world-leading hard X-ray ptychography instruments and to the relevance of these improvements for a wide range of applications, from materials science and battery research to biological imaging and in situ studies.

Synchrotron and XFEL Radiation

Co-Chairs: Daniel Decato & Johan Unge Sponsoring Commission: Electron Crystallography Co-Sponsoring Commission: Structural Chemistry Electron diffraction is becoming a mainstream technique for solving structures that are intractable by conventional X-ray diffraction methods. The use of electron diffraction has enabled the determination of many small-molecule structures, including difficult targets such as MOFs and natural products, often directly from powder samples. This session will focus on applications of electron diffraction to the study of small molecules and novel structures. Novel approaches in sample preparation, analysis, or areas of application that enable these structures are also encouraged.

Electron Crystallography
Structural Chemistry

Plenary