forthcoming articles
The following articles are a selection of those recently accepted for publication in IUCr journals.


Coherent crystal branches: tetragonal symmetry impact on 2D confined polymer nanostructure
The tetragonal crystal symmetry impact on the two-dimensional (2D) confined polymer nanostructure is demonstrated. Our research shows that this chain packing defect in the tetragonal cell can be controlled to develop along the rod long axis in 2D confinement.

Structural and functional analysis of the Klebsiella pneumoniae MazEF toxin-antitoxin system
We present the first crystal structure of a type II TA complex structure of K. pneumoniae at 2.3 Å resolution. Mutational experiments and cell growth assays confirm R28 and T51 as critical residues for MazF ribonuclease activity.

Whole pair distribution function modeling: the bridging of Bragg and Debye scattering theories
The whole pair distribution function modeling method is introduced to overcome the distinction between Bragg and Debye theories in analysis of powder scattering data. Models based on Bragg's law are used to facilitate the computation of a whole pair distribution function followed by solution of the Debye scattering equation.

Theoretical and experimental investigation of protein crystal nucleation in pores and crevices
Using a theoretical method which employs equilibration between the cohesive and destructive energies of a crystal, it is shown that protein layers of monomolecular thickness formed in pores can grow into macroscopic crystals. Experimental studies, stimulated from theoretical considerations, widen the palette of porous materials which can promote protein crystallization.

Structures of the germline-specific Deadhead and thioredoxin T proteins from Drosophila melanogaster reveal unique features among thioredoxins
The first structures of the Drosophila germline-specific thioredoxins Deadhead (Dhd) and thioredoxin T (TrxT), which present unusual properties with respect to canonical Trxs, are reported. Dhd is highly positively charged, which facilitates nonspecific DNA binding to promote chromatin remodeling. TrxT contains a C-terminal extension, which is mostly unstructured and highly flexible, that modulates the redox activity of the protein. These structures will facilitate the virtual screening of small-molecule ligands and protein partners.

Nitrosonium nitrate (NO+NO3−) structure solution using in situ single-crystal X-ray diffraction in a diamond anvil cell
The crystal structure of nitrosonium nitrate (NO+NO3−) is determined by synchrotron single-crystal X-ray diffraction at pressures of 7.0 and 37.0 GPa – resolving a long-standing controversy. Remarkably, the oxygen atom of the NO+ unit is determined to be positively charged, a rare occurrence when in the presence of a less-electronegative element.

![]() | Acta Crystallographica Section A Acta Crystallographica Section A FOUNDATIONS AND ADVANCES |

Isogonal piecewise linear embeddings of 1-periodic weaves and some related structures
Crystallographic descriptions of isogonal piecewise linear embeddings of 1-periodic weaves and links (chains) are presented. Many of these are interesting synthetic targets for reticular chemistry methods.

Multipole electron densities and structural parameters from synchrotron powder X-ray diffraction data obtained with a MYTHEN detector system (OHGI)
Multipole electron densities and structural parameters of inorganic and organic materials were evaluated on the basis of synchrotron powder X-ray diffraction data obtained with a MYTHEN detector system (OHGI).

Spin-resolved atomic orbital model refinement for combined charge and spin density analysis: application to the YTiO3 perovskite
The paper reports on a new crystallographic method to refine a spin-resolved atomic orbital model against X-ray and polarized neutron diffraction data. Radial extension of atomic orbitals, their orientations and populations are obtained for each atom in the YTiO3 perovskite crystal.

Arithmetic proof of the multiplicity-weighted Euler characteristic for symmetrically arranged space-filling polyhedra
A mathematical proof based on arithmetic argument is presented for the modified Euler characteristic χm =
(where the first summation runs from 0-dimensional vertices to the N-dimensional cell or `interior'), applicable to symmetrically arranged space-filling polytopes in N-dimensional space, where the contribution of each jth i-dimensional element of the polytope is weighted by a factor inversely proportional to its multiplicity m(ij).

Symmetry relations in wurtzite nitrides and oxide nitrides and the curious case of Pmc21
Binary and multinary nitrides in a wurtzitic arrangement are very interesting semiconductor materials. The group–subgroup relationship between the different structural types is established.
![]() | Acta Crystallographica Section B Acta Crystallographica Section B STRUCTURAL SCIENCE, CRYSTAL ENGINEERING AND MATERIALS |



Crystal structure of zinc(II) complexes with β-hydroxypyridinecarboxylate ligands: examples for structural directing effects used in inorganic crystal engineering
Structural directing effects of four [O,O] donor hydroxypyridinecarboxylate derivatives have been investigated in the complexation with Zn(II) by single crystal X-ray diffraction. One octahedral and two trigonal by-piramidal mononuclear complexes, as well as a pyridinolato bridged dimer with octahedral geometry, were detected.

Polymorphs of phenazine hexacyanoferrate(II) hydrate: supramolecular isomerism in a 2D hydrogen-bonded network
The crystal structures of two polymorphs of a phenazine hexacyanoferrate salt/cocrystal are presented. The polymorphs are remarkably similar, both comprising two-dimensional hydrogen-bonded networks built from the same supramolecular units.

Size effect of the guest cation on the AlO4 framework in aluminate sodalite-type oxides M8[Al12O24](SO4)2 (M = Sr2+ and Ca2+) in the I43m phase
Synchrotron radiation powder diffraction measurements and probability density function analyses of aluminate sodalite-type oxides Sr8[Al12O24](SO4)2 and Ca8[Al12O24](SO4)2 were performed in the cubic phases. The rotation of AlO4 in a tetrahedral framework was discussed.


The crystal structure of Cu2GeSe3 and the structure-types of the I2-IV-VI3 family of semiconducting compounds
Contrary to what has previously been reported, the structure of Cu2GeSe3 is found to be monoclinic (Cc, No. 9) and not orthorhombic (Imm2, No. 44) due to distortions as expected from bond valence model considerations.


A half-salamo-based pyridine-containing ligand and its novel NiII complexes including different auxiliary ligands: syntheses, structures, fluorescence properties, DFT calculations and Hirshfeld surface analysis
Three novel multinuclear NiII complexes with a half-salamo-based pyridine-containing ligand have been synthesized and characterized by FT–IR, UV–Vis absorption spectroscopy, X-ray crystallography, Hirshfeld surface analysis and density functional theory (DFT) calculations.
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![]() | Acta Crystallographica Section C Acta Crystallographica Section C STRUCTURAL CHEMISTRY |

Structural characterization and theoretical calculations of the monohydrate of the 1:2 cocrystal salt formed from acriflavine and 3,5-dinitrobenzoic acid
A monohydrate of the 1:2 cocrystal salt formed from acriflavine and 3,5-dinitrobenzoic acid was synthesized and structurally characterized. Detailed analysis and theoretical calculations of the intermolecular interactions occurring in the crystal, with an emphasis on interactions involving nitro groups, were carried out.
![]() | Acta Crystallographica Section D Acta Crystallographica Section D STRUCTURAL BIOLOGY |

Vagabond: bond-based parametrisation reduces overfitting for refinement of proteins.
Reparametrising the positions and flexibility of protein models for refinement against diffraction data results in a substantial reduction in the number of parameters. This produces maps less affected by model bias, which allow the maps to more faithfully reflect the true crystal contents and reveal more biological information.

Crystal structures of adenylylated and unadenylylated PII protein GlnK from Corynebacterium glutamicum
The crystal structures of the adenylylated and unadenylylated PII protein GlnK from C. glutamicum indicate that adenylylation of Tyr51 in the T-loop does not interfere with the PII-typical conformational changes that occur in the T-loop upon effector binding. The T-loop adenylylation rather further expands the repertoire of mechanisms that enable PII function.


The tetrameric structure of a novel haloalkane dehalogenase DpaA from Paraglaciecola agarilytica NO2
A novel type of haloalkane dehalogenase DpaA from Paraglaciecola agarilytica NO2 was successfully purified and crystallized. The DpaA model based on the crystallographic data reported here revealed the first example of a tetrameric structure in the haloalkane dehalogenase subfamily I.

Second distinct conformation of the phosphohistidine loop in succinyl-CoA synthetase
To discover a different conformation of the phosphohistidine loop in succinyl-CoA synthetase (SCS), GTP-specific SCS was co-crystallized with Mg2+-GDP and with Mg2+-GMPPNP and Mg2+-GMPPCP, which are nonhydrolysable analogues of Mg2+-GTP. In addition, phosphorylated GTP-specific SCS was co-crystallized with Mg2+-succinate and desulfo-CoA. The phosphohistidine loop was observed with the active-site histidine residue at the nucleotide-binding site, and a second succinate-binding site was revealed.

Structure and comparison of the motor domain of centromere-associated protein E
Crystallization and structure determination of the motor domain of centromere-associated protein E in complex with its inhibitor was performed. In the determined structure, endogenous ADP was observed in the nucleotide-binding site instead of the inhibitor.


Structural insights into the substrate-binding cleft of AlyF reveal the first long-chain alginate-binding mode
The structure of the alginate lyase AlyF in complex with the long alginate oligosaccharide G6 revealed the whole substrate-binding cleft and the role of three flexible loops involved in substrate binding. Accordingly, a `fishing-like' substrate-binding model was proposed for AlyF.


more ...
![]() | Acta Crystallographica Section E Acta Crystallographica Section E CRYSTALLOGRAPHIC COMMUNICATIONS |

Crystal structure and Hirshfeld surface analysis of 3-amino-1-oxo-2,6,8-triphenyl-1,2,7,8-tetrahydroisoquinoline-4-carbonitrile
The supramolecular structure of the compound is stabilized by a three-dimensional array of N—H⋯O and C—H⋯N hydrogen bonds and C—H⋯π interactions.

Synthesis and structure of 4-{(E)[(7-methoxy-1,3-benzodioxol-5-yl)methylidene]amino}-1,5-dimethyl-2-phenyl-2,3-dihydro-1H-pyrazol-3-one
The reaction of 4-amino-1,5-dimethyl-2-phenyl-1,2-dihydropyrazol-3-one with 4-methoxybenzo[1,3]dioxole-5-carbaldehyde resulted in the title compound, which crystallizes in space group C2/c. Two solvent-accessible voids, each of 397 Å3, were found to be evident in the crystal structure.

Crystal structure of a 1,1-dibutyl-1H,3H-naphtho[1,8-cd][1,2,6]oxastannaborinin-3-ol
A novel oxastannaborininol, 1,1-dibutyl-1H,3H-naphtho[1,8-cd][1,2,6]oxastannaborinin-3-ol, has been synthesized and crystallized. It is the first reported compound with a heterocycle containing an Sn–O–B unit.

Crystal structure of 1,2-bis(4-fluorophenyl)-1-hydroxy-2,3,8-trimethoxyacenaphthene: formation of a five-membered intramolecular O—H⋯O hydrogen-bonded ring
In the crystal of the title compound, the formation of an intramolecular O–H⋯O hydrogen bond between the hydroxy group and the methoxy group at the 1,2-positions of the acenaphthene ring core giving rise to a five-membered cyclic organization is observed. In the molecular packing, a pair of non-classical C—H⋯O hydrogen bonds forms centrosymmetric dimeric structures.

Crystal structures of three copper(II)–2,2′-bipyridine (bpy) compounds, [Cu(bpy)2(H2O)][SiF6]·4H2O, [Cu(bpy)2(TaF6)2] and [Cu(bpy)3][TaF6]2 and a related coordination polymer, [Cu(bpy)(H2O)2SnF6]n
The crystal structures of three copper(II)-bipyridine–MF6 (M = Si, Ta, Sn) compounds and a related coordination polymer are reported.

Crystal structures of [Cu(phen)(H2O)3(MF6)]·H2O (M = Ti, Zr, Hf) and [Cu(phen)(H2O)2F]2[HfF6]·H2O
Crystal structures of three compounds with the formula [Cu(phen)(H2O)3(MF6)]·H2O (M = Ti, Zr, Hf) based on bimetallic Λ-shaped molecules and a related salt with the formula [Cu(phen)(H2O)2F]2[HfF6]·H2O are reported.

Crystal structure of the RuPhos ligand
The solid-state structure of RuPhos (2-dicyclohexylphosphanyl-2′,6′-diisopropoxybiphenyl) is presented for the first time and discussed in detail. The phosphine cone angle is computed and compared to the cone angles of other phosphine ligands.
![]() | Acta Crystallographica Section F Acta Crystallographica Section F STRUCTURAL BIOLOGY COMMUNICATIONS |

Structural insights into the intermolecular interaction of the adhesin SdrC in the pathogenicity of Staphylococcus aureus
S. aureus SdrC forms a unique dimer through homophilic interactions, and a sandwich-like clamp at the C-terminus is formed by the two monomers in the stabilized SdrC dimer. Comparison with other Sdr proteins led to the proposal of a model for the confomational change of SdrC upon ligand binding.
![]() | Journal of Applied Crystallography Journal of Applied Crystallography |

Influence of surface relaxation on the contrast of threading edge dislocations in synchrotron X-ray topographs under the condition of g · b = 0 and g · b × l = 0
Surface relaxation contributes to the formation of residual contrast of threading edge dislocations in X-ray back reflection topographs under = 0 and × = 0 conditions.

Polo: An Open-Source Graphical User Interface for Crystallization Screening
A multi-platform open-source Python-based graphical user interface has been developed to provide access to automated classification and data management tools for biomolecular crystallization screening.



crystIT: complexity and configurational entropy of crystal structures via information theory
Information theory provides an intriguing framework for evaluating the complexity of a crystal structure. This article provides an improvement to the current theory and describes the integration of the updated formulas into an open-source Python-based program called crystIT.

The anisotropy in the optical constants of quartz crystals for soft X-rays
The refractive index of a y-cut SiO2 crystal surface is reconstructed from polarization-dependent soft X-ray reflectometry measurements in the energy range from 45 to 620 eV. The reconstructed anisotropy in the optical constants is also confirmed by ab initio Bethe–Salpeter equation calculations of the O K edge.

A simulational study of the indirect-geometry neutron spectrometer BIFROST at the European Spallation Source, from neutron source position to detector position
The incident detector rates that are anticipated for the indirect-geometry cold-neutron spectrometer BIFROST at the European Spallation Source are estimated, and the use of powerful simulation tools for the correct interpretation of neutron transport in crystalline materials is demonstrated.



On the structural formula of smectites: a review and new data on the influence of exchangeable cations
The fit of the smectite structural formula is reviewed. In addition, a group of samples, both dioctahedral and trioctahedral, are studied, demonstrating the influence of interlaminar Mg that can lead to the erroneous classification of smectite if it is not considered.
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![]() | Journal of Synchrotron Radiation Journal of Synchrotron Radiation |



Study of the X-ray radiation interaction with a multislit collimator for the creation of microbeams in radiation therapy
The study of the synchrotron X-ray radiation interaction with a multislit collimator is a critical factor for the creation of microbeams in radiation therapy. This study is a fundamental step forward in the understanding and definition of a reliable protocol for dosimetry at the micrometric scale to be used in microbeam radiation therapy.


Feasibility of X-ray beam nanofocusing with compound refractive lenses
The problem of X-ray beam nanofocusing with compound refractive lenses is examined in detail. It is shown that the minimum beam size is independent of either the aperture or photon energy but depends only on the compound refractive lens material electron density.

Effect of germanium auto-diffusion on the bond lengths of Ga and P atoms in GaP/Ge(111) investigated X-ray absorption spectroscopy
Integration of high crystalline structures of III–V semiconductors on Si and Ge is the prime requirement for the implementation of highly efficient and economically viable nano-photonic devices. EXAFS results of GaP/Ge(111) obtained using a synchrotron radiation source provided excellent insight and proposed new possibilities within the GaP/Ge hetero-structure, such as the conversion from indirect to direct band structures and engineering the tensile strain quantum dot structures on (111) surfaces.


FMX – the Frontier Microfocusing Macromolecular Crystallography Beamline at the National Synchrotron Light Source II
The new Frontier Microfocus Macromolecular Crystallography beamline FMX in sector 17-ID-2 of the National Synchrotron Lightsource II provides an ultra-bright microfocus beam and a flexible experimental station for structure determination from the most challenging crystals.

Redox state and photoreduction control using X-ray spectroelectrochemical techniques – advances in design and fabrication through additive engineering
The design and operation of a 3D-printed flow in situ electrochemical cell suitable for ambient-temperature X-ray absorption spectra measurements is described. The ability to control, and significantly limit, photoreduction whilst requiring only small solution volumes make this a superior sampling approach to cryogenic techniques for many samples.

The 1-Megapixel pnCCD detector for the Small Quantum Systems Instrument at the European XFEL: system and operation aspects
A description of the 1-Megapixel pnCCD detector design and capabilities, its implementation at EuXFEL's Small Quantum Systems Instrument both mechanically and from the controls side as well as important data correction steps aim to provide useful background for users planning and analyzing experiments at EuXFEL and may serve as a benchmark for comparing and planning future endstations at other FELs.
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![]() | IUCrData IUCrData |

rac-11-Selena-12,13-diazabicyclo[10.3.0]pentadeca-10a(13a),12-dien-1-ol
The title compound crystallizes in strands of enantiomeric molecules connected via O—H⋯N hydrogen bonds. There are only slight deviations from an ideal gauche conformation in the decamethylene chain, indicating just a little strain.

2-(2,4-Dinitrophenyl)-1-(pyridin-4-yl)ethanol monohydrate
In the title compound, the dihedral angle between the aromatic rings is 9.60 (7)° and the chain linking the rings has an anti conformation with a torsion angle of −178.28 (12)°. In the crystal, the components are linked by O—H⋯O and O—H⋯N hydrogen bonds, generating (010) sheets.