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Two T–X binary phase diagrams have been constructed between salicylic acid (SA) and two monotropic polymorphs of the isomer 3-hydroxybenzoic acid (3HBA). Crystalline solid solutions (CSS) were formed at all extremes of the phase diagrams. The solid-state miscibilities ranged from 0.5% up to 6% of the second component. The thermodynamically stable form I of 3HBA exhibited a higher solid state miscibility than form II of 3HBA across all investigated temperatures. The solubility changes induced by the different CSS were measured experimentally in 40 w% methanol in water at 25 °C and are presented in two ternary phase diagrams. The SA-rich CSS phase exhibited the highest solubility increase corresponding to 160% up to the solvus at 0.7% 3HBA in SA. The changes in solubility of the CSS phases belonging to the two 3HBA polymorphs were found to diverge with increasing incorporation of SA in the respective crystal lattices. This thermodynamic divergence in combination with the monotropic stability relationship caused the driving force for polymorphic conversion to increase with increasing SA content. This unusual scenario was demonstrated experimentally through the use of solution-mediated phase transformation (SMPT) experiments analyzed in situ by Raman. It was found that the incorporation of 0.5% SA in the crystal lattice of 3HBA form II caused the polymorphic conversion rate to form I to double, in comparison to when 3HBA is chemically pure. The current example thus demonstrates the thermodynamic context for how solid-state miscible impurities can expedite polymorphic conversions. This and other contributions showcase how the rates of crystallization can be enhanced or reduced solely based on formation of CSS with an impurity or additive, without accounting for any surface adsorption effects. [ABSTRACT FROM AUTHOR]

Quaternion and biquaternion symmetry transformations have been applied to non-Cartesian reference systems of direct and reciprocal crystal lattices. The transformations performed directly in the sets of crystal reference axes simplify the calculations, eliminate the need for orthogonalization, permit the use of crystallographic vectors for defining the directions of rotations and perform the computations directly in the crystal coordinates. The applications of the general quaternion transformations are envisioned for physical, chemical, crystallographic and engineering applications. The general quaternion multiplication rules for any symmetry-unrestricted lattices have been derived for the triclinic crystallographic system and have been applied to the biquaternion representations of all point-group symmetry elements, including the crystallographic hexagonal system. Cayley multiplication matrices for point-groups, based on the biquaternion symbols of proper and improper symmetry elements, have been exemplified. [ABSTRACT FROM AUTHOR]

This work explores the synthesis and DFT study of five tetranuclear Pb(II) complexes and the role of tetrel bonding in their crystal engineering. Three synthesised Pb(II) complexes and two theoretical tetrameric Pb(II) complexes with halogenated thiophene carboxylate and 1,10-phenanthroline ligands are reported here. Their structural configurations, which feature chair-like repeating units connected via oxygen bridges, without Pb–Pb bonds, show two types of packing arrangements. Each Pb atoms form hemidirectional coordination creating space for the formation of tetrel bonds. The close packed arrangements are stabilised and guided by tetrel bonds. The Pb⋯Br tetrel bonds were found to contribute −4.38 kcal mol−1 and Pb⋯Cl −3.37 kcal mol−1 for the stability of the complexes. These tetrel bonds direct the packing arrangements within the crystal lattice. Additionally, open packed arrangements are stabilised by hydrogen bonds. These findings offer new insights into the design of lead-based metal organic frameworks and highlights the critical role of tetrel bonds in the crystal architecture. [ABSTRACT FROM AUTHOR]

The long-range periodic atomic arrangement or the lack thereof in solids typically dictates the magnitude and temperature dependence of their lattice thermal conductivity (κlat). Compared to crystalline materials, glasses exhibit a much-suppressed κlat across all temperatures as the phonon mean free path reaches parity with the interatomic distances therein. While the occurrence of such glass-like thermal transport in crystalline solids captivates the scientific community with its fundamental inquiry, it also holds the potential for profoundly impacting the field of thermoelectric energy conversion. Therefore, efficient manipulation of thermal transport and comprehension of the microscopic mechanisms dictating phonon scattering in crystalline solids are paramount. As quantized lattice vibrations (i.e., phonons) drive κlat, atomistic insights into the chemical bonding characteristics are crucial to have informed knowledge about their origins. Recently, it has been observed that within the highly symmetric 'averaged' crystal structures, often there are hidden locally asymmetric atomic motifs (within a few Å), which exert far-reaching influence on phonon transport. Phenomena such as local atomic off-centering, atomic rattling or tunneling, liquid-like atomic motion, site splitting, local ordering, etc., which arise within a few Å scales, are generally found to drastically disrupt the passage of heat carrying phonons. Despite their profound implication(s) for phonon dynamics, they are often overlooked by traditional crystallographic techniques. In this review, we provide a brief overview of the fundamental aspects of heat transport and explore the status quo of innately low thermally conductive crystalline solids, wherein the phonon dynamics is majorly governed by local structural phenomena. We also discuss advanced techniques capable of characterizing the crystal structure at the sub-atomic level. Subsequently, we delve into the emergent new ideas with examples linked to local crystal structure and lattice dynamics. While discussing the implications of the local structure for thermal conductivity, we provide the state-of-the-art examples of high-performance thermoelectric materials. Finally, we offer our viewpoint on the experimental and theoretical challenges, potential new paths, and the integration of novel strategies with material synthesis to achieve low κlat and realize high thermoelectric performance in crystalline solids via local structure designing. [ABSTRACT FROM AUTHOR]

Molecular crystals that exhibit photomechanical responses show great promise as photoactuators and other smart materials in various fields. Herein, we synthesized two new barbituric acid derivative crystals (crystals 1 and 2), which exhibit distinct photomechanical responses towards a laser irradiation of 532 nm and UV LED photoirradiation of 365 nm, respectively. Crystal 1 demonstrated photomechanical bending upon exposure to 532 nm laser, whereas crystal 2 exhibited dramatic bursting, followed by jumping of its fragments upon UV irradiation. The photomechanical responses of both crystals are attributed to the [2 + 2] photocycloaddition reaction. However, their different kinematic responses are related to different amounts of accumulated strain energy owing to photocycloaddition and its subsequent release in the crystal lattice. The accumulation of strain energy depended on various factors such as the structural arrangement of the crystals, packing modes and overall directionality of non-covalent interactions. Furthermore, the position of the olefinic bond and peripheral substituents played a key role in determining the development of strain energy. [ABSTRACT FROM AUTHOR]

An organic 5‐methyl‐1H‐imidazole‐3‐ium‐4‐carboxybutanoate (5MIC) co‐crystal is grown by slow evaporation solution growth technique (SEST) at room temperature. The 5MIC is synthesized using 4‐methylimidazole and glutaric acid in a 1:1 ratio using methanol as a solvent. The 5MIC crystal lattice parameters are identified using single‐crystal X‐ray diffraction analysis. The experimental X‐ray diffraction (XRD) and DFT structural parameter values have good correlations. The intermolecular interactions of the 5MIC crystal are found using Hirshfeld surface and 2D fingerprint plots. The computed C–N stretching vibration of the imidazole ring is observed at 1498, 1233, and 1064 cm−1. The HOMO is located on 4‐methylimidazole moiety of 5MIC molecule. Densities of state are used to find out the molecular orbital compositions of the 5MIC molecule. Mulliken analysis shows that the C13 (−0.86) atom has the lowest negative charge. The MEP surface color coded of 5MIC lies between 7.950 e−3 and −7.950 e−3. The 5MIC molecule has four types of intermolecular transitions. The first‐order hyperpolarizability (β) value of 5MIC molecule is 5.48×10−30 esu. The 5MIC crystal is thermaly stable up to 146 °C. The photoluminescence emission is observed from 400 to 600 nm. The 5MIC crystal shows SHG characteristics. [ABSTRACT FROM AUTHOR]

Almost no diffraction broadening of self-collimation beams and their easy crossing with low crosstalk offer new opportunities for acoustic wave manipulation. Here, we flexibly steer the self-collimation beam based on the total internal reflection of an airborne square lattice sonic crystal. The properly designed crystal/air interface may serve well as a total internal reflection mirror of the self-collimation beam, with which we are able to achieve the highly controllable beam reversal, snaking and crossing. Our scheme can be extended to more interesting beam steering, and have potential applications in constructing high-density integrated acoustic circuits. [ABSTRACT FROM AUTHOR]

Three polymorphs of N4-ethyl-N1-(diphenylphosphoryl)acetyl-thiosemicarbazide, which exemplify packing polymorphism, are obtained and characterized. Polymorphs have the same molecular conformation stabilized by the intramolecular N–H⋯O hydrogen bond and the morphology of primary 1D crystal-forming motifs. The main difference of one of the polymorphs is known to be due to a change in the type of the hydrogen bonding acceptor and the arrangement of molecules in the 1D motif. In the other two polymorphs with the identical 1D motif, the difference consists in the arrangement of 2D layers formed by weaker interactions. Despite that the parallel packing of 2D layers for the polymorph with two independent molecules appears to be somewhat more favorable than the antiparallel packing occurring in the polymorph crystal with Z′ = 1, the DSC results indicate that the latter is the thermodynamic form under normal conditions. It is shown that the polymorphs are characterized by a similar structural organization of crystal lattices which consists in the localization of regions containing hydrophilic and hydrophobic molecular fragments in the crystals. [ABSTRACT FROM AUTHOR]

Yb:CALYGLO crystals with a dopant concentration of 5 at.% were successfully grown using the Czochralski method. The crystal samples were extensively studied to analyze their structure, room temperature and low temperature spectra, and laser properties. The highest absorption cross-section at 977 nm was calculated to be 1.83 × 10−20 cm2 for σ polarization and 5.32 × 10−20 cm2 for π polarization. Similarly, the emission cross-section was determined to be 1.38 × 10−20 cm2 at 980 nm for σ polarization and 2.28 × 10−20 cm2 at 981 nm for π polarization, with a full width at half maximum (FWHM) of 50.3 nm and 89.5 nm, respectively. The fluorescence lifetime of the 5 at.% Yb:CALYGLO crystal at 2F5/2 was measured to be 1.10 ms. Additionally, gain cross-sections were calculated for different β values. In the continuous laser experiment, the crystal demonstrated a laser output of 20.15 W at 1057 nm, with a slope efficiency of 53.3%. These experimental findings indicate that the lattice of Y3+ in the crystal is partially replaced by Lu3+ and Gd3+, resulting in a broader spectrum. Consequently, this crystal shows promising potential as a gain medium for ultrashort pulse laser crystals. [ABSTRACT FROM AUTHOR]

Spontaneous ordering in a system of excited emitters with a powerful short radiation pulse predicted by Dicke attracted the great attention of scientists for decades as a bright example of the nontrivial behavior of a nonequilibrium system. The Bogolyubov reduced description method has some advantages and provides new possibilities in the theoretical investigation of the Dicke process. The paper presents the authors' results of modeling such processes concerning both optical ones in the presence of crystal lattice influence and acoustic superradiance, which is possible in solids. The right choice of reduced description parameters allows the account of atom motions (phonons), cavity influence, and excitations in the emitter system (excitons) in the electromagnetic radiation process. The mathematical analogy between the Dicke system and a spin system in a magnetic field opens the way to applying the reduced description technique to acoustic phenomena previously investigated with the boson variable elimination method. Such a new approach to superradiance in crystals with paramagnetic impurities and with competing mechanisms of relaxation (Wagner model) is outlined. Acoustic superradiance is discussed in connection with the problem of structural phase transitions. [ABSTRACT FROM AUTHOR]

Six-dimensional hard hypersphere systems in the A6, D6, and E6 crystalline phases have been studied using event-driven molecular dynamics simulations in periodic, skew cells that reflect the underlying lattices. In all the simulations, the systems had sufficient numbers of hyperspheres to capture the first coordination shells, and the larger simulations also included the complete second coordination shell. The equations of state, for densities spanning the fluid, metastable fluid, and solid regimes, were determined. Using molecular dynamics simulations with the hyperspheres tethered to lattice sites allowed the computation of the free energy for each of the crystal lattices relative to the fluid phase. From these free energies, the fluid–crystal coexistence region was determined for the E6, D6, and A6 lattices. Pair correlation functions for all the examined states were computed. Interestingly, for all the states examined, the pair correlation functions displayed neither a split second peak nor a shoulder in the second peak. These behaviors have been previously used as a signature of the freezing of the fluid phase for hard hyperspheres in two to five dimensions. [ABSTRACT FROM AUTHOR]

Metastability of many-body quantum states is rare and still poorly understood. An exceptional example is the low-temperature metallic state of the layered dichalcogenide 1T-TaS2 in which electronic order is frozen after external excitation. Here we visualize the microscopic dynamics of injected charges in the metastable state using a multiple-tip scanning tunnelling microscope. We observe non-thermal formation of a metastable network of dislocations interconnected by domain walls, that leads to macroscopic robustness of the state to external thermal perturbations, such as small applied currents. With higher currents, we observe annihilation of dislocations following topological rules, accompanied with a change of macroscopic electrical resistance. Modelling carrier injection into a Wigner crystal reveals the origin of formation of fractionalized, topologically entangled networks, which defines the spatial fabric through which single particle excitations propagate. The possibility of manipulating topological entanglement of such networks suggests the way forward in the search for elusive metastable states in quantum many body systems. The metastable state with a complex domain structure in 1T-TaS2 has been intensively studied. Using a multi-tip scanning tunnelling microscope, Mraz et al. reveal the microscopic dynamics of the current-pulse-induced metastable state and interpret it in terms of transport in a doped Wigner crystal lattice. [ABSTRACT FROM AUTHOR]

Thermal treatment of linear dipeptides in solid state makes it possible to obtain their cyclic analogues in high yield and without additional expenses. At the same time, such reactions occurring under the conditions of crystal lattice restrictions with the participation of molecules in the zwitterionic form have not been sufficiently studied. In this work, the cyclization reaction of the L-leucyl-L-valine dipeptide in the crystalline phase upon heating was studied. Using isoconversion kinetics approaches, a kinetic model describing this process was found, and kinetic parameters were calculated, including activation energy, Arrhenius factor, and reaction order. The enantiomeric purity of the resulting cyclic product was assessed. The self-assembly of linear and cyclic dipeptides on a solid substrate was studied. The results of the study will be useful in determining mechanisms of the cyclization reactions of dipeptides in the solid state, and can also be used in the development of effective and cost-efficient methods for the production of cyclic dipeptides. [ABSTRACT FROM AUTHOR]

In this study, the fabrication of a large bulk crystal based on the hybrid structure of CH3NH3PbBr3 (MAPBr) and PbS quantum dots (QDs) with excellent crystal lattice match using an in situ epitaxial crystallization technique is presented. The hybrid bulk crystal is successfully constructed by uniformly dispersing PbS QDs within the MAPBr matrix. The crystalline growth method is also changed to achieve the desired hybrid structure. The light emission range is modulated and the light emission lifetime is prolonged by constructing a MAPBr‐PbS hybrid structure. Additionally, the hybrid bulk crystal exhibited an up‐conversion effect, which does not appear in MAPBr single crystal. These findings highlight the promising potential of the MAPBr‐PbS QDs hybrid bulk crystal in the fields of optics and photoelectronic, such as all solid‐state lasers, bio‐imaging, optical data storage, and photovoltaic applications. This in situ hybrid crystallization technique also provides a universal pathway for the preparation of other bulk crystals based on perovskite‐QDs hybrid structures. [ABSTRACT FROM AUTHOR]

Crystallographic literature is relying more on observational rules for the determination of the motif that could generate the whole representing Bravais lattice of a crystal. Here, we devise an algebraic method that can serve in this regard at least in cases when the associated unit cell is made of quasi-orthogonal vectors. To let our approach be applicable to other reduction problems, we introduce a concept which is about starting first from any ’bad’ crystal cell, not necessarily the primitive elementary cell, in order to find a ’good’ crystal cell and that means seeking a motif made of a basis whose vectors are close-to-orthogonal. The orthogonalization loss could happen any time of vectors swapping which represents a very important process in dealing with lattice reduction, but it has insufficiently been discussed in this subject. Thus, through our present version of vectors exchange theorem, and by using examples of two processes, namely the Gram-Schmidt (GS) procedure and its modified version (MGS), we provide formulations for the new reduced unit cell vectors and analyze the impact of the repeated exchange of vectors on the orthogonalization precision. Finally, we give a detailed explanation to our procedure named as Abdelalim-Elmouki (AE) algorithm. More interestingly, we show that MGS is not only better than GS because of the classical reason related to numerics, but also because its formulation for the new motif vectors in four conditions, has been preserved in three times rather than two for GS, and this may recommend more the introduction of MGS in a harder problem, namely when the crystal dimension is very big. [ABSTRACT FROM AUTHOR]

The lattice parameters of A2XY6 (A = K, Cs, Rb, and Tl; X = tetravalent cation; Y = F, Cl, Br, and I) cubic crystals play significant roles in designing materials for specific technological applications and uniquely describe the material crystal structure. Despite the importance of its lattice parameters, the experimental determination of these parameters requires special sophisticated equipment, while the first principle calculation consumes appreciable time and might need complex software packages. The existing empirical relation in the literature is characterized by large percentage deviation, and the recently proposed machine learning support vector regression method cannot be empirically implemented on new compounds. This present work fills the research gap through the development of empirical relation between the lattice parameters, electronegativity and ionic radii of the constituting ions using extreme learning machine (ELM) with the grid search (GS) hyper-parameters optimization method. The proposed model is developed through the analysis of atomic structural properties of 85 crystals that serve as representatives of the A2XY6 group. On the basis of a mean absolute percentage error, the developed GS-ELM model outperforms the existing Brik and Kityk [J. Phys. Chem. Solids 72(11), 1256–1260 (2011)] model with a percentage improvement of 58.37%, while it performs better than Alade et al. [J. Appl. Phys. 127(1), 15303 (2020)] model with the percentage enhancement of 37.90%. The outstanding performance of the proposed GS-ELM model coupled with its ease of implementation would be of great significance by enhancing the search for new materials tailored to targeted application and preventing lattice constant mismatch in thin film fabrication. [ABSTRACT FROM AUTHOR]

The present paper investigates the F-type centers in α-Al2O3 through their electronic and vibrational properties from first principle calculations using a periodic supercell approach, a hybrid functional, and all-electron Gaussian basis sets as implemented in the CRYSTAL17 code. Single F-type and dimer F2-type centers related to oxygen vacancies in various charge states were considered. The defect-induced vibrational modes were identified and found to appear mainly in the low (up to 300 cm−1) and high (above 700 cm−1) frequency regions, depending on the defect charge. The perturbation introduced by the defects to the thermal nuclear motion in the crystal lattice is discussed in terms of atomic anisotropic displacement parameters. The calculated Raman spectra are discussed for the first time for such defects in α-Al2O3, suggesting important information for future experimental and theoretical studies and revealing deeper insight into their behavior. [ABSTRACT FROM AUTHOR]

A semi-organic nonlinear optical crystal of L-alanine nickel chloride (LAN) has been successfully grown by a slow evaporation solution method. The single-crystal x-ray diffraction technique determined the lattice parameters of the crystal. Fourier-transform infrared spectral analysis confirmed the functional groups present in the crystal lattice. The crystal was subjected to UV–Visible-NIR transmittance measurements, and its band-gap energy was determined using transmittance studies. A Nyquist plot was used to determine the crystal's bulk resistance and dc conductivity. Fluorescence analysis was performed on the crystal, and green visible light was emitted from it when it was excited by UV light. Microhardness measurements were made on the crystal, and numerous parameters were analyzed. We studied the crystal's nonlinear optical properties, while its magnetic properties were determined using a vibrating sample magnetometer. TGA/DTA analysis was performed on the crystal, and it was found that its Second-harmonic Generation efficiency was more than that of the standard KDP sample. Hence, this crystal could be useful in laser technology, optical communication, optical computing, optical data processing, and photonics. [ABSTRACT FROM AUTHOR]

The study of heterogeneous reactions for enantiomeric processes based on inorganic crystals has been resurgent in recent years. However, the question remains how homochirality develops in nature and chemical reactions. Here, the successful growth of B20 group PdGa single crystals with different chiral lattices enabled us to achieve enantioselective recognition of 3,4‐dihydroxyphenylalanine (DOPA) based on a new mechanism, namely orbital angular momentum (OAM) polarization. The orbital textures of PdGa crystals indicate large OAM polarization near the Fermi level and carrying opposite signs. A positive or negative magnetization in the [111] direction is expected depending on the chiral lattice of PdGa crystals. Due to this, the adsorption energies of PdGa crystals and DOPA molecules differ depending on how well the O‐2p orbital of DOPA pairs with the Pd‐4d orbital of PdGa. The results provide one possible explanation for how chirality arises in nature by providing an enantioselective route with pure inorganic crystals. [ABSTRACT FROM AUTHOR]

Fluorescent plastically bendable crystals are a promising alternative to silicon‐based materials for fabricating photonic integrated circuits, owing to their optical attributes and mechanical compliance. Mechanically bendable plastic organic crystals are rare. Their formation requires anisotropic intermolecular interactions and slip planes in the crystal lattice. This work presents three fluorescent plastically bendable crystalline materials namely, 2‐((E)‐(6‐methylpyridin‐2‐ylimino)methyl)‐4‐chlorophenol (SB1), 2‐((E)‐(6‐methylpyridin‐2‐ylimino)methyl)‐4‐bromophenol (SB2), and 2‐((E)‐(6‐Bromopyridin‐2‐ylimino)methyl)‐4‐bromophenol (SB3) molecules. The crystal plasticity in response to mechanical stress facilitates the fabrication of various monolithic and hybrid (with a tip‐to‐tip coupling) photonic circuits using mechanical micromanipulation with an atomic force microscope cantilever tip. These plastically bendable crystals act as active (self‐guiding of fluorescence) and passive waveguides both in straight and extremely bent (U‐, J‐, and O‐shaped) geometries. These microcircuits use active and passive waveguiding principles and reabsorbance and energy‐transfer mechanisms for their operation, allowing input‐selective and direction‐specific signal transduction. [ABSTRACT FROM AUTHOR]

A crystal lattice is the three-dimensional structural arrangement of atoms or molecules inside a crystalline solid as points. Each crystal lattice consists of repeating unit cells in different directions. From earlier scientific research, it was recognised that the physio-chemical properties of any crystal structure lattice are highly reliant on the molecular structure of the network. This study led us to investigate complex structures through a mathematical perspective using a chemical invariant (topological index) by a chemical graph theory that correlates a chemical graph structure and physio-chemical properties, where atoms represent the nodes and a bond between atoms is considered as an edge. In this research, we have given explicit expressions for eccentricity-based chemical invariants, namely, eccentric connectivity (EC), total eccentricity (TE), eccentricity-based Zagreb (EZ) and connective eccentric (CE) for inorganic symmetrical Hexagonal Close-Packed (H C P (U)) and Hexagonal ( H E X (U)) crystal structure lattices. [ABSTRACT FROM AUTHOR]

The ordered Ca3TaGa3Si2O14 and disordered La3Ga5SiO14 crystals of the lantangallium silicate family were grown via the Czochralski method. The independent coefficients of thermal expansion of crystals α c and α a were determined using X-ray powder diffraction based on the analysis of X-ray diffraction spectra measured in the temperature range of 25~1000 °C. It is shown that, in the temperature range of 25~800 °C, the thermal expansion coefficients are linear. At temperatures above 800 °C, there is a nonlinear character of the thermal expansion coefficients, associated with a decrease in the Ga content in the crystal lattice. [ABSTRACT FROM AUTHOR]

With the aim of giving prominence to the ability and dominance of phenolic acid nutrient p-coumaric acid (TPA) towards ameliorating the medicinal properties of BCS class-IV antifungal drug bifonazole (BFZ), a cocrystallization-driven tactic for perfecting peculiarity and assisting enhancement efficacy has been put forward. This strategy fully exploits the structural features and property advantages of TPA to lift both the solubility and permeability of the parent drug BFZ through a cocrystallization technique, and at the same time, to heighten the antifungal effect of the drug. Directed by this strategy, a novice cocrystallization complex of BFZ and TPA, namely BFZ–TPA, as the first BFZ cocrystal, is successfully assembled and structurally identified by a variety of analytical means. Single-crystal X-ray diffraction analysis confirms that the BFZ and TPA molecules in the cocrystal are connected through a classical O1–H1A⋯N2 hydrogen-bonding synthon in a stoichiometric ratio of 1 : 1, constructing an intact three-dimensional supramolecular structure. Thereinto, the TPA molecule with a rigid planar structure is filled into the crystal lattice of BFZ via intermolecular interaction, producing a more compact and stable crystal structure landscape. Such a structural trait and accumulation pattern make both the solubility and permeability of BFZ in the cocrystal increased by 3.60- and 2.27-fold in comparison with drug BFZ per se, which can be strongly validated by DFT-based theoretical calculations. Intriguingly, these optimized physicochemical properties significantly enhance the antifungal effect of the cocrystal, exhibiting larger inhibition rings and lower MIC values. Therefore, this work not only contributes a crystalline solid form with a brand-new structure and potential application prospects for BFZ, thus filling the gap of BFZ cocrystal research, but also opens a new application pathway of phenolic acid nutrition in the field of antifungal cocrystal drugs. [ABSTRACT FROM AUTHOR]

Metasurfaces are of great interest as they exhibit unique electromagnetic properties. Currently, metasurface design focuses on generating new meta-atoms and their combinations. Here a topological database, reticular chemistry structure resource (RCSR), is introduced to bring a new dimension and more possibilities for metasurface design. RCSR has over 200 two-dimensional crystal nets, among which 72 are identified as suitable for metasurface design. Using a simple metallic cross as the metaatom, 72 metasurfaces are constructed from the atom positions and lattice vectors of the crystal nets templates. The transmission curves of all the metasurfaces are calculated using the finite-difference time-domain method. The calculated transmission curves have good diversity, showing that the crystal nets approach is a new engineering dimension for metasurface design. Three clusters are found for the calculated curves using the K-means algorithm and principal component analysis. The structure–property relationship between metasurface topology and transmission curve is investigated, but no simple descriptor has been found, indicating that further work is still needed. The crystal net design approach developed in this work can be extended to three-dimensional design and other types of metamaterials like mechanical materials. [ABSTRACT FROM AUTHOR]

It is shown that the quadrature derivatives in some analytical gradients of energies evaluated with a multi-centre radial-angular grid do not vanish even in the limit of an infinitely dense grid, causing severe errors when neglected. The gradients in question are those with respect to a lattice constant of a crystal or to the helical angle of a chain with screw-axis symmetry. This is in contrast with the quadrature derivatives in atomic gradients, which can be made arbitrarily small by grid extension. The disparate behaviour is traced to whether the grid points depend on the coordinate with respect to which the derivative of energy is taken. Whereas the nonvanishing quadrature derivative in the lattice-constant gradient is identified as the surface integral arising from an expanding integration domain, the analytical origin of the nonvanishing quadrature derivative in the helical-angle gradient remains unknown. [ABSTRACT FROM AUTHOR]

Spinels have a rich history that spans complexities of their structures to multitude of useful properties and intriguing phenomena. Herein, we demonstrate the versatility and elegance of ferrite-spinel based magnetic nanostructures (MNSs) as a contrast agent in magnetic resonance imaging (MRI). We show that the magnetic properties of the inverse spinel Fe3O4 MNS can be enhanced by tuning their crystal chemistry. After doping with Mn2+ and Zn2+ into Fe3O4 MNS at a right stoichiometry, high saturation magnetization and magnetic anisotropy were observed due to rearrangement and specific positions of Mn2+, Zn2+, Fe2+, and Fe3+ cations in the inverse spinel AB2O4 crystal lattice. The improved magnetic properties were leveraged to develop T1-weighted MRI contrast agent that are more biocompatible and efficient than currently used Gd-based complexes. This work underscores the rich opportunities in magnetic spinels for not only unusual applications as in MRI contrast enhancement but also the complexity and versatility of its crystal chemistry that forms the basis for its diverse properties. [ABSTRACT FROM AUTHOR]

ZrSiO 4 -based ceramics have been considered as one of the candidate nuclear waste forms, while the immobilization behavior of mixed-valent uranium in the structure of the ceramics was unclear. Herein, ZrSiO 4 –U ceramics with a general formula of Zr 1-4 x (U6+ x U5+ 2 x)SiO 4 were designed and synthesized. The evolutions of phase and microstructure depending on the content of U were investigated. The ceramics with 0 ≤ x < 0.04 showed a single ZrSiO 4 phase, while U 3 O 8 phase was detected when x ≥ 0.04. The results demonstrated that the solubility limit of U in ZrSiO 4 ceramic was up to 1.51 at.% or 11.06 wt%. The calculated lattice parameters increased with the increase of U content. The increased parameters provided the evidence of the immobilization of both U5+ and U6+ into ZrSiO 4 crystal lattice by replacing Zr4+. Furthermore, the obtained ZrSiO 4 –U ceramics exhibited good aqueous durability (∼10−5 g m−2 d−1). The results indicated that ZrSiO 4 -based ceramics can be employed to effectively immobilize mixed-valent U. [ABSTRACT FROM AUTHOR]

The article presents the results of experimental studying the hysteresis of water contact angles at crystalline surfaces. Receding and advancing contact angles and their hysteresis at hydrophilic and hydrophobic substrates with different surface structures (silica, mica, and calcite) have been studied under the action of an external pressure applied to the three-phase contact line of a sessile air bubble. Hysteresis of the contact angles has been observed on hydrophobized samples of silica and mica. The anchoring of the three-phase contact line (pinning) facilitates a change in the contact angles under the applied external pressure. When the three-phase contact line moves along the hydrophilic surfaces of silica and mica no marked changes in the advancing and receding contact angles are observed, and the hysteresis is actually absent. The stable pinning observed on the polished surface of a calcite crystal brought in contact with water leads to the appearance of contact angle hysteresis and hydrophilization of the calcite surface, with the hydrophilization being related to structural displacements in the crystal lattice. [ABSTRACT FROM AUTHOR]

Equilibrium parameters of the crystal lattice are obtained by the methods of density functional theory. The electronic structure and vibrational properties of hypothetical AlSi2P and GaGe2As crystals, analogs of the superhard BC2N crystal, has been studied. The energy band structure, long-wave oscillation frequencies at point Г, elastic moduli, Poisson's ratio, and microhardness are calculated. The role of group IV elements is established and the contributions of the vibrations of individual atoms to the vibrational modes of the crystal are determined. [ABSTRACT FROM AUTHOR]

High-quality pentacene-doped p-terphenyl bulk crystals were grown by the selective self-seeding vertical Bridgman technique (SSVBT). The lattice structure and crystal properties of the samples of different doping concentrations and their relations with p-terphenyl single crystals were tested and analyzed. The doping effects of pentacene doping at different concentrations in p-terphenyl molecular crystals are discussed. The powder X-ray diffraction, FTIR, and 1H NMR studies show that no additional peaks (except for p-terphenyl) are observed in the spectra of two doped crystals. The results indicate that guest molecules appear as defects in the form of irregularly oriented molecules which do not significantly change the crystal structures. As the doping concentration increases, the average crystallite size decreases, and the crystallinity declines. The ultraviolet–visible absorption and fluorescence spectra show that with added pentacene molecules, the characteristic peak intensities decrease in the spectra owing to the p-terphenyl molecular transition. Meanwhile, characteristic peaks appear due to the pentacene molecular transition. Moreover, with the increase of doping concentration, the intensities of characteristic peaks of host molecules decrease continuously, and those of guest molecules increase accordingly. [ABSTRACT FROM AUTHOR]

Most recently discovered active pharmaceutical molecules and market-approved medicines are poorly soluble in water, resulting in limited drug bioavailability and therapeutic effectiveness. The application of coformers in a multicomponent crystal method is one possible strategy to modulate a drug's solubility. A multicomponent crystal is a solid phase formed when several molecules of different substances crystallize in a crystal lattice with a certain stoichiometric ratio. The goal of this review paper is to comprehensively describe the application of coformers in the formation of multicomponent crystals as solutions for pharmaceutically active ingredients with limited solubility. Owing to their benefits including improved physicochemical profile of pharmaceutically active ingredients, multicomponent crystal methods are predicted to become increasingly prevalent in the development of active drug ingredients in the future [ABSTRACT FROM AUTHOR]

The photochromic transformation of color centers in γ-irradiated yttrofluorite crystals with disordered crystal lattice formed in the binary system of CaF2–YF3 solid solutions at different contents of yttrium fluoride has been studied. The photochromic transformation of РС+ centers into a РС center was shown to occur under UV irradiation. It was found that the participation of UV-induced photoelectrons of γ-induced F-centers should be taken into account in the consideration of the mechanism of РС+ → РС transformation. An effect of the structure disordering on the increase in the intensity of absorption spectral bands of РС color centers is revealed. [ABSTRACT FROM AUTHOR]

Crystal engineering provides a unique approach to modulating the physicochemical properties of forming active drug molecules so nowadays pharmaceutical companies and researchers have shown interest in designing and building cocrystals. Creating new crystalline solid structures with altered physicochemical properties such as solubility, bioavailability, tabletability, melting point, stability, and so on. The intermolecular interactions of molecules in the crystal lattice are used to investigate these properties. Numbers of methods for crystallizing the drug are summarised and analyzed, pointing to the advantages and disadvantages that have been highlighted in the literature. This literature review discusses in detail the different types of cocrystals, their mechanisms, methods of cocrystals, applications of cocrystals, and their characterization. The main purpose of this article is to look at what has changed in this field in the last ten years and show what could be learned from better research on cocrystal formation and how it can be used. [ABSTRACT FROM AUTHOR]

The influence on HMX impact sensitivity resulting from damage due to phase transition versus that of the polymorphic conformer and crystal lattice change in δ-HMX are quantified in this work. Microstructural imaging techniques are used to characterize 30 crystals from three groups of distinctly large and small HMX crystals which have undergone a thermally induced phase transition, as well as some which have undergone spontaneous reversion from δ → β -phase. It is found that large HMX crystals incur a significant increase in cracks during the transition from β → δ , while much smaller crystals appear to have no distinguishable increase in voids after undergoing a β → δ -phase change. Drop-weight impact experiments were performed on 46 to 68 samples from each of six sample types of HMX, three types of which are composed of very small HMX crystals and three of which are composed of large HMX crystals. It is found that small HMX crystals, which do not appear to incur a significant increase in voidspace after undergoing the phase transition, do not have statistically distinguishable changes in drop-weight impact sensitivity between β, δ, or β-reverted phase HMX; however, large crystal HMX impact sensitivity increases significantly when transitioned to δ-phase and furthermore when allowed to revert to β-phase. This indicates that the morphological change is the dominant effect of β → δ transformation on impact sensitivity and that the δ-conformer and crystal packing structure have little or no effect on the impact sensitivity of HMX. [ABSTRACT FROM AUTHOR]

In materials science, crystal lattice structures are the primary metrics used to measure the structure–property paradigm of a crystal structure. Crystal compounds are understood by the number of various atomic chemical settings, which are associated with Wyckoff sites. In crystallography, a Wyckoff site is a point of conjugate symmetry. Therefore, features associated with the various atomic settings in a crystal can be fed into the input layers of deep learning models. Methods to analyze crystals using Wyckoff sites can help to predict crystal structures. Hence, the main contribution of our article is the classification of crystal classes using Wyckoff sites. The presented model classifies crystals using diffraction images and a deep learning method. The model extracts feature groups including crystal Wyckoff features and crystal geometry. In this article, we present a deep learning model to predict the stage of the crystal structure–property. The lattice parameters and the structure–property commotion values are used as inputs into the deep learning model for training. The structure–property value of a crystal with a lattice width value of one-half millimeter on average is used for learning. The model attains a considerable increase in speed and precision for the real structure–property prediction. The experimental results prove that our proposed model has a fast learning curve, and can have a key role in predicting the structure–property of compound structures. [ABSTRACT FROM AUTHOR]

Software from the MiCMoS Molecular Simulation platform (sites.unimi.it/xtal_chem_group/) and from the CryGen set of programs (www.angelogavezzotti.it) is used to prepare a molecular structure from a line formula for a non‐existent molecule, dubbed 'fakein'. Possible crystal structures are generated in chiral space groups P21 and P212121, and for racemate in space groups P1− and P21/c. Lattice energies and crystal densities are in line with experimental values for organic molecules. Chiral crystals are less stable, and may not easily form hydrogen bonds, while bulk crystal stabilization is provided mostly by polarization‐dispersion. Hydrogen bonding and crystal packing are discussed in terms of molecular pairing modes. Links to possible experiments and to absolute crystal structure prediction are outlined, but the main aim here is to demonstrate that relevant solid‐state information can be derived if that goal is not achieved, actually even if the real substance is not available. [ABSTRACT FROM AUTHOR]

An analytical and numerical study of hybrid photonic–plasmonic crystals is presented. The proposed theoretical model describes a system composed of a dielectric photonic crystal on a metallic thin film. To show the validity and usefulness of the model, four particular structures are analyzed: a one-dimensional crystal and three lattices of two-dimensional crystals. The model can calculate the photonic band structure of photonic–plasmonic crystals as a function of structural characteristics, showing two partial bandgaps for a square lattice, and complete bandgaps for triangular lattices. Furthermore, using a particular high-symmetry path, a full bandgap emerges in rectangular lattices, even with a small refractive index contrast. Using the analytical model, a dataset is generated to train an artificial neural network to predict the center and width of the bandgap, that is, the forward design. In addition, an artificial neural network is trained to tune the optical response, that is, to perform the inverse design. The analytical results are consistent with the physics of the system studied and are supported by numerical simulations. Moreover, the prediction accuracy of the artificial neural networks is better than 95%. Overall, this paper reports a useful tool for tuning the optical properties of hybrid photonic–plasmonic crystals with potential applications in waveguides, nanocavities, mirrors, etc. [ABSTRACT FROM AUTHOR]

Lead-free zero-dimensional (0D) perovskite nanocrystals (NCs) with isolated octahedral structures have attracted considerable attention due to their unique photoelectric properties, such as highly efficient emissions with broadband features. A series of phosphors composed of Sb3+-doped 0D perovskite crystals Cs3ZnCl5 with wavelength-tunable emission spectra have been obtained using a facile recrystallization method at room temperature in air. By controlling the doping concentration of Sb3+ in Cs3ZnCl5 lattice, bright emissions from red to orange have been achieved under excitation at 320 nm due to the expansion of the crystal lattice, and the emission excited at 275 nm is bluish-white, spanning the full visible region. Inductively coupled plasma emission spectrometry (ICP) demonstrates the Sb3+ substitutes for Zn2+ rather than Cs+ due to the similar charges and ionic radii. The luminescence performance of phosphor Cs3ZnCl5:Sb3+ can be improved obviously by replacing 3 mol% of Cs+ with Rb+ or K+ due to the further distortion of the crystal lattice. The present approach allows the synthesis of large-scale emissive lead-free 0D perovskites activated by Sb3+ with tunable luminescence color. [ABSTRACT FROM AUTHOR]

Background. The study of the physicochemical properties of raw materials production of iodized sodium salt, the improvement of environmentally friendly technologies for its production is relevant for the republic as iodine deficiency. Purpose: Development of a technology for obtaining sustainable iodized table salt during comprehensive processing of local sulfate and chloride saline deposits. Methodology. As the original, the cleaned brine of JSC “KungradSodovaya Plant” was used. The additive of potassium iodide in the form of a saturated solution varied from 1 to 10 ml/l of the purified solution. With the achievement of a given degree of evaporation, the liquid and solid phases was divided by filtration, the fractional composition and ratio of phases was determined. Originality. Changes in the chemical and fractional composition of products are determined depending on the technological parameters of the crystallization process, optimal conditions for its conduct in the presence of potassium iodide at a temperature of 25 are established; 60 and 100°C, the physico-chemical and commodity properties of iodized table salt are determined; Findings. Microscopic and X-ray phase analysis methods have found that potassium iodide crystals are obeyed, introducing into the crystal lattice of sodium chloride, which ensures the stability of iodine in gathered salt. [ABSTRACT FROM AUTHOR]

Torasemide is a loop diuretic drug. The poor aqueous solubility of the drug is of concern and there is a need to improve its properties. Pharmaceutical salt formation is a promising approach for solubility enhancement. Except for the HCl salt, there are no reports on the salts of torasemide and systematic studies of solubility improvements are also lacking. Three novel crystalline salts have been identified which are torasemide fumarate, torasemide oxalate and torasemide oxalate methanol solvate. The crystalline salts are characterized by crystallographic (SCXRD and PXRD), spectroscopic (FT-IR and NMR) and thermal (DSC, TGA and HSM) methods. The expected drug–coformer stoichiometry (2 : 1 or 1 : 0.5) is achieved only in the case of the torasemide oxalate crystalline salt (1 : 0.5) whereas torasemide fumarate crystallizes in a 1 : 1 drug–coformer stoichiometry. The methanol solvate of torasemide oxalate represents a special situation. It crystallizes in a 2 : (0.5 + 0.5) drug–coformer stoichiometry, wherein the two independent half molecules of oxalate anions are, although chemically the same, crystallographically distinct, conceptually being a Z′ = 2 structure. These results indicate that besides fulfilling the complementarities of acid–base functionalities for effective salt formation, other factors like accommodation of drug and coformer molecules in the crystal lattice through adjustments in their stoichiometry, conformational variations, hydrogen bonds, and solvent of crystallization could play a critical role in the development of energetically favourable crystalline solids. Compared to the parent torasemide drug, the salts have shown enhanced solubility profiles (18 times for fumarate salt and 14 times for oxalate salt). Similarly, the salts have shown a very rapid dissolution pattern (≥85% in ≤15 minutes) in simulated gastric fluid (pH 1.2) and phosphate buffer medium (pH 6.8) whereas the dissolution of the T-I polymorph of torasemide is only 57% in simulated gastric fluid and 66% in phosphate buffer. The crystalline salts of torasemide with improved solubility and dissolution profiles may find their applications in the development of formulations where a rapid onset of diuretic effect is desired. [ABSTRACT FROM AUTHOR]

Thermodynamic computer models of real alloys are based, first of all, on the choice of a particle interaction potential. The chosen potential often determines, to a great extent, the final result. The potential should numerically describe the properties of investigated materials qualitatively and as accurately as possible. The aim of this study is to analyze numerically the properties of the Ni3Al and Pt3Al crystals using the potentials obtained by the embedded-atom method (EAM). Classical EAM potentials and modified EAM (MEAM) potentials are considered with allowance for directional bonds. The lattice parameters, phonon spectra, elastic constants, and melting points of the proposed fcc intermetallics with the L12 superstructure have been calculated. The characterization of the crystals with the maximum accuracy allows one to construct realistic thermodynamic models with a required degree of reliability in studying localized states of the crystal lattices. The alloys under study find wide application, in particular, under intense external impacts. This leads to the manifestation of nonlinearity of the bonds and the formation of various localized states both in the bulk of the crystals and on their surface. In particular, solitary waves, nonlinear localized modes, and defect structures can be formed. The results obtained show that the investigated potentials describe satisfactorily the main properties and can be used to study the lattice dynamics in the bulk of a crystal. At the same time, the MEAM potentials seem preferable in studying surface effects and boundary temperature and pressure parameters. [ABSTRACT FROM AUTHOR]

The effect is studied theoretically of nonreciprocity of interparticle forces on the Brownian motion of a single-layer plasma crystal with the hexagonal lattice. The interaction potential used is the potential of a point charge in plasma consisting of the Maxwellian electrons and directed flow of cold ions. It is shown that in the spectral density of particle displacements, there is a large number of singularities that occur due to the presence of critical points at frequencies corresponding to different oscillation branches. When approaching the threshold for developing the instability of coupled waves, the synchronous correlation matrices of velocities indicate the considerable deviation from the law of kinetic energy equipartition over degrees of freedom. [ABSTRACT FROM AUTHOR]

Potassium dihydrogen phosphate (KDP) single crystals doped with a series of trace dichromate (Cr 2 O 7 2−) were prepared using "point seed" technique. The IR spectra suggest that the KDP crystal network becomes compact with trace of Cr 2 O 7 2− while the lattice of crystal also can be destroyed by excessive doping. The UV–Vis spectra show that the transmittance percentage is descended of the doped KDP crystals. Z-scan analysis demonstrates that with increasing of Cr 2 O 7 2− concentration, a gradual raise has been observed for the nonlinear absorption coefficient (β). The laser-induced damage threshold (LIDT) at 532 nm of the KDP crystal doped with 3000 ppm Cr 2 O 7 2− is found to be 28.29 J/cm2 which is higher than that of pure one under the R-on-1 model. However, as the doping concentration continues to increase, the LIDT decreases significantly. The variation of photoluminescence (PL) results is also consisted with the trend of LIDT for the doped samples. The LIDT of pyramidal sample is higher than that of prismatic one with the same doping concentration. The results suggest that the laser damage of doped crystal may be due to a synergistic effect of the concentration of micro defects and nonlinear absorption. [ABSTRACT FROM AUTHOR]

The paper specifies the Dixon–Cohen method for the experimental determination of the acousto–optical figure of merit M2. In particular, the conditions are formulated when the Dixon–Cohen method application for M2 determination is possible without significant errors. Cases are considered when the condition of the “weak field” in the studied material is not satisfied, as well as when the transmission of the studied and reference materials is less than 100%. The error in determining the acousto–optical figure of merit M2 in the case of unenlightened test material, using CaWO4 and GaP crystals as an example, is estimated, and the limits of application of the “weak field” approximation in these two crystals are established. [ABSTRACT FROM AUTHOR]

Doping is an important means to control the properties of diamond. In this paper, the P-doped diamond large single crystals were synthesized by temperature gradient method at 5. 6 GPa and 1 312 ℃ using Fe3P as the phosphorus source. The results of the optical micrographs of diamond samples show that as the amount of Fe3P additve increases, the color of diamond crystals becomes darker, the number of inclusions increases in the crystals, and the crystal shape transforms from plate to tower, even to skeletal. It indicates that the V-shaped growth region shifts to the right when Fe3P is added. This is due to Fe3P has effect on the properties of the catalyst. IR spectra of P-doped diamond reveal that the concentrations of nitrogen impurity in the diamond crystals increases with the increase of the Fe3P content. It indicates that the entry of phosphorus induces nitrogen atoms to enter the diamond lattice more easily. Raman spectra results show that with the increase of Fe3P content, the Raman peak positions of the synthesized diamond change little, but the FWHM becomes larger. This suggests that the entry of phosphorus increases the crystal lattice distortion of diamond. XPS test results show that with the increase of Fe3P, the content of P relative to C in diamond crystal also increases. It means that phosphorus are present in the diamond crystals synthesized by Fe3P addition. [ABSTRACT FROM AUTHOR]

Noble metal decoration of wideband gap semiconductors enables the excitation of surface plasmons in the visible range that upon relaxation generate hot carriers used for catalysis. However, this strategy leads to photocatalytic conversion efficiencies that are still low. Here, a light‐trapping scheme is used to amplify the light‐harvesting efficiency of the TiO2 semiconductor beyond the UV region by coupling a 2D‐photonic crystal to Au decorated titania. This approach is easily scalable using soft nanoimprinting lithography to prepare Au/TiO2 2D‐photonic photocatalysts. In a first process, gold nanoparticles (Au NPs) are in situ infiltrated in the superficial 50 nm of a mesoporous titania (mTiO2) scaffold patterned with the photonic structure, while in a second one 2D‐photonic crystals with a homogeneous volume distribution of the Au colloids are achieved. The dependence of the optical properties of the photonic crystals on the lattice parameter, geometry, and metal loading is presented through extinction measurements and analyzed through simulations. The improved photocatalytic performance of the substrates is tested for hydrogen production where a maximum of 8.5 mmol gcat−1 h−1 of H2 is recorded and attributed to photonic–plasmonic effects. These results may open new avenues in solar harvesting for hydrogen production using photonic crystals as photocatalysts. [ABSTRACT FROM AUTHOR]

The magnetic properties of the mixed spin − 1/2 and spin − 1 Ising ferrimagnetic nanotube with a hexagonal lattice in the presence of the crystal field are investigated by means of the finite cluster approximation. We examine the effects of the crystal field, the surface shell, and core coupling parameters where the main attention has been paid to study the magnetizations and also the phase diagrams for both transition and compensation temperatures. In the absence of the crystal field, the compensation behavior exists only in a limited range of surface shell and core couplings. By introducing a crystal field, the compensation behavior is maintained and the tricritical behavior occurs depending on the strength of surface shell coupling. [ABSTRACT FROM AUTHOR]