Zero-dimensional (0D) perovskites are promising materials due to their structures comprising isolated metal halide octahedra or clusters, which impart remarkable optoelectronic properties. The synthesis, crystal structure and Hirshfeld surface analysis of the title compound, 1,4-diazoniabicyclo[2.2.2]octane hexabromidostannate(IV) hemihydrate, (C6H14N2)[SnBr6]·0.5H2O or (DABCO)[SnBr6]·0.5H2O, are reported. The compound crystallizes in the monoclinic space group P21/n. Dominant H...Br/Br...H interactions (90.5%) are observed, with smaller contributions from H...H (5.1%), Br...Br (4.2%) and O...Br/Br...O (0.1%) contacts. These structural features underline the role of hydrogen bonding in stabilizing the 0D framework, highlighting its potential for light-emitting and photonic applications.

In the binuclear title complex, [La2(C2H3O2)4(C11H10N4)(H2O)4](NO3)2·0.5H2O, the two lanthanum ions are nine coordinate in a distorted trigonal–prismatic geometry. Each LaIII ion is bonded to three N atoms of the Schiff base, 1-(pyridin-2-yl)-2-(pyridin-2-ylmethylene)hydrazine and is coordinated by one acetate group, which acts in η2-bidentate mode and two acetate groups that act in μ2-mode between the two LaIII ions. Two η1-water molecules complete the coordination sphere. All bond lengths in the coordination environment of the LaIII ion are slightly larger than those observed in the isostructural NdIII and SmIII complexes. The LaIII...LaIII distance is 4.6696 (6) Å. In the crystal, extensive O—H...O hydrogen-bonding interactions involving the coordinated water molecules and the non-coordinating nitrate anions, as well as the oxygen atoms of the acetate groups, generate an overall three-dimensional supramolecular network.

In the title compound, C16H9BrO4, the dihedral angle between the chromen-2-one ring system (r.m.s. deviation = 0.006 Å) and the bromobenzene ring is 10.29 (6)°. In the crystal, the molecules are connected through C—H...O hydrogen bonds and π–π stacking interactions. According to a Hirshfeld surface analysis, H...H (22.4%), O...H/H...O (23.6%) and C...H/H...C (21%) interactions are the most significant contributors to the crystal packing.

The experimental electron density distribution of p-O2NC6F4CNSSN center dot, a dithiadiazolyl radical, has been determined from a high-resolution X-ray diffraction experiment at 100 K. The atomic charges obtained according to Bader partitioning through integration over the atomic basins reveal charge transfer from the -CNSSN ring to the -NO2 moiety. There is an electric polarization of the molecule along the 2-fold axis in the [110] direction, which is also a symmetry axis of the molecule. Analysis of the topological properties of the electron density has evidenced a range of interactions. The presence of a bond critical point along the SN contacts previously identified as significant for communication between spins confirms an intermolecular interaction between these spin-bearing atoms. Particular attention has been given to the charge density spatial orientation around the sulfur and nitrogen atoms because of the previously identified role of these atoms in the appearance of ferromagnetism at very low temperatures.

In the title compound, C20H18O4, the dihedral angle between the 2H-chromen-2-one ring system and the phenyl ring is 89.12 (5)°. In the crystal, the molecules are connected through C—H...O hydrogen bonds to generate [010] double chains that are reinforced by weak aromatic π–π stacking interactions. The unit-cell packing can be described as a tilted herringbone motif. The H...H, H...O/O...H, H...C/C...H and C...C contacts contribute 46.7, 24.2, 16.7 and 7.6%, respectively, to its Hirshfeld surface.

Single crystals of bis(1,2-diaminepropane) di-μ-chloro-bis[diaquadichloromanganate(II)] dichloride have been prepared by evaporation from ethanoic solution. The triclinic X-ray crystal structure is built as layers of centrosymmetric dimers of [Mn(Cl)4(H2O)2]2- octahedra and 1,2-diaminopropane. The inorganic part consists of Mn octahedra sharing one edge and distributed in the basal ac plane along the a direction. These doubly negative charged layers are separated along the b axis by a positively charged diamine propane layer. One Cl- anion contributes to the electroneutrality of the crystal interacting with both inorganic - through a hydrogen bond network to the two water molecules coordinated to Mn - and organic layers via the NH3+ ammonium group. Differential scanning calorimetry shows two endothermic main peaks at T = 366 K and T = 375 K related to the release of the water molecules. The resulting dehydrated material is C-centered monoclinic as shown by powder X-ray diffraction.

The growth and thermal stability of the gallic acid : nicotinic acid cocrystal has been analyzed in terms of electron density analysis and conversion of GA monohydrate into anhydrate through heating the co-crystal.

The growth and stability of a new 1 : 1 antipyrene–dichlorobenzoic acid cocrystal system has been analyzed in terms of electron density analysis and electrostatic interaction energy contributions.

crystallographic crystal band transport metal-insulators magnetic and dielectric properties, optical mechanical phase diagrams, synthetic strategies,

A new crystallographic method is proposed in order to refine a spin-resolved atomic orbital model against X-ray and polarized neutron diffraction data. This atomic orbital model is applied to the YTiO3 perovskite crystal, where orbital ordering has previously been observed by several techniques: X-ray diffraction, polarized neutron diffraction and nuclear magnetic resonance. This method gives the radial extension, orientation and population of outer atomic orbitals for each atom. The interaction term between Ti3+, Y3+ cations and O2- ligands has been estimated. The refinement statistics obtained by means of the orbital method are compared with those obtained by the multipole model previously published.

Experimental electron density analysis by means of high-resolution X-ray diffraction data up to sinθ/λ max = 1.11 Å −1 at 100 (1) K has been performed to analyze the detailed structure and the strength of intermolecular interactions responsible for the formation of a new solid form of nicotinic acid (NA), cocrystallized with pyrogallol (PY). There are two NA–PY units in the asymmetric unit. The experimental results are compared with the results obtained from theoretical structure factors modeled using periodic boundary DFT calculations. Both refinements were carried out using the Hansen and Coppens multipolar formalism (in MoPro program). The non-centrosymmetric and polar nature of the crystal system rendered the multipolar refinement challenging which was addressed by involving the transferability principle. This study highlights the significance of the transferability principle in electron density modeling in non-routine situations. The 2:2 cocrystal of NA–PY exhibits a zigzag, brickwall and sheet-like layered structure in three dimensions and is stabilized by strong intra- and inter-molecular hydrogen bonding through N—H...O and O—H...O bonds, some of them due to the zwitterion nature of NA as well as weak interactions between the PY molecules. Ranking these interactions via topological analysis of the electron density shows the leading role of the NA–NA substructure which drives the organization of the cocrystals. These strong interactions between the NA zwitterions may explain why Z ′ = 2.

MOLLYNX is a new crystallographic tool developed to access a more precise description of the spin-dependent electron density of magnetic crystals, taking advantage of the richness of experimental information from high-resolution X-ray diffraction (XRD), unpolarized neutron (UND) and polarized neutron diffraction (PND). This new program is based either on the well known Hansen–Coppens multipolar model (MOLLYNX-mult) or on a new expansion over a set of atomic orbitals (MOLLYNX-orb). The main difference between the two models is the basis of the expansion: in MOLLYNX-mult the expansion is over atom centered real spherical harmonics, in MOLLYNX-orb the expansion is over a set of atomic orbitals with which mono and bicentric contributions are calculated. This new approach of MOLLYNX-orb can also be applied to nonmagnetic crystals. This paper summarizes the theoretical ground of two models and describes the first applications to organic, organometallic and inorganic magnetic materials

We are developing in the CRM2 laboratory a new software: Mollynx. As MoPro or XD, Mollynx is derived from Molly (Hansen and Coppens, 1978) but allows to differentiate the electron spins. This new algorithm has been successively applied to paramagnetic coordination compounds (Deutsch et al., 2012, Deutsch et al., 2014) to organic radicals (Voufack et al., 2017) and to small unit cells inorganic crystals (Voufack et al., 2019). A more general model based on atomic orbitals (Tanaka, 1988; Tanaka, 1993; Bytheway et al., 2001; Schweitzer, 2006), has also been coded in the Mollynx software. This model should allow calculation of properties derived from the atomic wave functions such as covalency, populations of atomic orbitals, energy, optical properties and can in principle describe bonded pair of atoms with orbitals centered on different atoms (two centres orbital products). This model, extended to spin resolved orbitals, has been applied to the YTiO 3 perovskite (figure 1, Kibalin et al., 2021) The radial extension, orientation and population of outer atomic orbitals for each atom have been modelled leading to a clear description of the bonding in this crystal . Thus Mollynx can refine

Polymorphism in Molecular Crystals which the late Professor Bernstein wrote in 2002.This second edition describes major progress in the understanding of polymorphism, from the experimental procedures to show this important property, to applications in fundamental crystallography, structure-properties relationships, material sciences and pharmacology.Many well selected examples are discussed which guide a new researcher into the field.It is also a fantastic source of historical, fundamental and up to date papers and reviews (110 pages of references).This book then can be read by a beginner in the field but also by an active researcher in polymorphism, crystal engineering or crystal chemistry.The author took care to allow the reader to go directly to the information with a well documented index.Even if it is not defined like that by J. Bernstein, this book is divided into five parts: the first part (chapters 1 to 5) is devoted to fundamentals, analytical and modelling techniques, followed by one general chapter entitled Polymorphism and Structure-Property relations.Then comes the applications to pharmaceuticals, pigments and dyes, highenergy materials.The book ends with the important topic of polymorphism and patents.Some comments on chapters: Chapter 2 Fundamentals.This chapter is very chemistry oriented: this is understandable, but some physics about phase transitions could have been useful.Many figures have been reproduced from papers or reviews but sometimes the legends or/and the corresponding text do not help for fully understanding the information of the figure (for example, Figures 2.4 to 2.8).Chapter 3 Exploring the crystal landscape describes the challenge to discover and control the characterizing polymorphism (including disappearing polymorphs) from a thermodynamic and kinetic point of view.Paragraphs on solvent choice, non-traditional techniques and high throughput are especially interesting.Chapter 4 Analytical Techniques: the most relevant techniques and methods to characterize polymorphs are described: not extensively (it is not the aim of the book) for the usual ones such as X-ray powder or single-crystal diffraction, thermal methods, NMR, IR, Raman spectroscopies, microscopies, but enough to understand which technique should be used for which characterization.The section on optical hot-stage microscopy is very informative.The combination of X-ray diffraction with other methods, such as timeresolved diffraction are also introduced; these new methods (not technologies as written in the book) should have been more developed.Chapter 5 Computational aspects.First a thorough discussion on conformational polymorphs is given, then methods to calculate ÁU and ÁG are proposed with selected examples.The chapter on prediction of polymorphs describes very honestly all blind tests made in collaboration with the Cambridge Structural Database.A large chapter is devoted to Hirshfeld surfaces, which in my opinion, is too long as most information given by Hirshfeld surfaces can be retrieved quantitatively not qualitatively from critical inspection of intermolecular distances and angles.A paragraph on the experimental analysis of the molecular interactions using Bader's Atoms in Molecules theory from high-resolution X-ray diffraction results and/or DFT would have been welcome.

4-[(Morpholin-4-yl)carbothioyl]benzoic acid, C12H13NO3S, a novel phenyl(morpholino)methanethione derivative, crystallizes in the monoclinic space group P21/n. The morpholine ring adopts a chair conformation and the carboxylic acid group is bent out slightly from the benzene ring mean plane. The molecular geometry of the carboxylic group is characterized by similar C—O bond lengths [1.266 (2) and 1.268 (2) Å] as the carboxylate H atom is disordered over two positions. This molecular arrangement leads to the formation of dimers through strong and centrosymmetric low barrier O—H...O hydrogen bonds between the carboxylic groups. In addition to these intermolecular interactions, the crystal packing consists of two different molecular sheets with an angle between their mean planes of 64.4 (2)°. The cohesion between the different layers is ensured by C—H...S and C—H...O interactions.