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In this paper, the crystallization behavior of a novel poly(monothiocarbonate), poly(trimethylene monothiocarbonate) (PTMMTC), was investigated and compared with its polycarbonate analogue, poly(trimethylene carbonate) (PTMC). It is found that PTMMTC exhibits strong crystallizability, while unstretched PTMC is amorphous. DSC and DMA results reveal that PTMMTC possesses higher glass transition temperature (Tg) and β-transition temperature (Tβ) than PTMC. Simulation based on density functional theory (DFT) shows that, the bond angle of C-S-C is evidently smaller than that of C-O-C, and thus a larger dipole moment. This leads to the stronger intermolecular interaction and more rigid chain conformation in PTMMTC, which is the origin of sulfur-substitution enhanced crystallization. The crystal structure of PTMMTC was preliminarily determined for the first time. PTMMTC has an orthorhombic crystal structure with a planar zig-zag chain conformation. The parameters of unit cell are a = 10.74 A, b = 4.79 A, and c (fiber axis) = 7.74 A.

A glass ceramic from the MgO–Al2O3–SiO2 system containing additives of ZrO2, TiO2, La2O3 and P2O5 was investigated. Via x-ray powder diffraction (XRPD) and Transmission electron microscopy(TEM) the crystalline phases present could be identified as MgAl2O4 (Spinel), orthorhombic ZrTiO4 and a polymorph of LaPO4 with a previously unknown crystal structure. The crystal structure of this LaPO4 phase was solved ab initio via 3D ED Data. The polymorph occurs in a distorted barite structure type in the same space group (P21/n) as the stable monazite type polymorph, however the density is higher and the La has a higher coordination number. Furthermore the LaPO4 is present in a spinodal relict microstructure. Potential explanations for the presence of this metastable polymorph are pressure due to residual stresses from the crystallization or surface effects due to the high surface area resulting from the spinodal relict structure.

Formation of β′ phase in long-period stacking ordered (LPSO) structures in an Mg88Co5Y7 (at.%) alloy after aging at 200 °C for 24 h or electron beam (EB) irradiation has been studied by high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). β′ phase was precipitated only in the Mg matrix but not in LPSO structures after aging at 200 °C for 24 h. LPSO structure containing stacking defects transforms into the β′-long phase during EB irradiation, which plays a key role in accelerating solute atoms’ diffusion. New complex β′(LPSO) structures formed in the alloy after EB irradiation, such as β′(12H) structure with an orthorhombic lattice (Mg7Y, Cmcm, a = 2a0 = 0.642 nm, b = 4 3 a0 = 2.27 nm, c = 6c0 = 3.12 nm).

Semiorganic single crystals of L-Threonine Lithium Chloride were wealthy developed by slow evaporation method at ambient circumstances. The structure was illuminated by single crystal XRD technique and the structure be owned by orthorhombic system. Density functional theory computations using B3LYP/6-311++ G(d,p) base set gives optimized structural parameters of title compound. The Theoretically identified hyperconjugative molecular interactions are accountable for the stabilization of compound are obtain by NBO analysis. Besides, Mulliken atomic charges and molecular electrostatic potential were also executed.

Screening of AgNO3/AgStBu solutions in DMF, DMSO and NMP resulted in an isolation of three novel nanosized silver/thiolate complexes with a torus-like {Ag20(StBu)10} core. The structures of [NO3@Ag20(StBu)10(NO3)9(DMF)6] (1) and [NO3@Ag20(tBuS)10(NO3)8(NMP)8][NO3@Ag19(tBuS)10(NO3)8(NMP)6]2(NO3) (2) were studied by SCXRD. The self-assembly process leading to 1 can be switched to a different outcome by Br–, resulting in [Br@Ag16(StBu)8(NO3)5(DMF)3](NO3)2 (3), which is the one of the few genuine host-guest complex in the silver/thiolate systems. Solutions of the individual complexes in CH3CN were studied by HR-ESI-MS techniques, which revealed a dynamic behavior for each complex, driven by a redistribution of the {AgNO3} units. This dynamics results in the appearance of both cationic and anionic species, based on unchanged silver-thiolate cores. Day light causes degradation of 3 with the formation of a composite material based on defective orthorhombic Ag2S with a porous morfology, as observed with SEM technique. Electrocatalytic HER activity of such material was studied.

Present paper reports the study of single crystal X-ray diffraction of the compound 4-Amino-N-(3-chloropyrazin-2yl)benzene-1-sulfonamide which crystallizes in an orthorhombic crystal system with the space group Pbca having precise unit cell parameters a = 11.5260(19)A, b = 9.6270(16)A, c = 22.099(5)A, Z = 8 and V = 2452.1(8)A3. The structure was solved by direct methods and was refined by full-matrix least-squares based on F2. After subsequent cycles of refinement, the structure was converges to the Goodness-of-Fit (S) = 1.33. The molecule was adopted as a non-planar structure with a dihedral angle of 89.95°. In the crystal, molecules are held together through intermolecular N–H…O and C–H…O interactions. The nitrogen (N) atom of pyrazine ring has exhibited trifurcated intramolecular relations through C–H…N, N…C, and N…O incorporating S(5), S(6), and S(7) ring motifs, respectively. The intermolecular interactions were analyzed, and their percentage of contribution towards crystal packing was computed using Hirshfeld surface analysis. Also, interaction energies between the different pairs of molecules were analyzed, visualized and estimated using the energy density model of B3LYP/6-31G(d,p).

In the present study, copper (II) complex of 4, 4′-di-tert-butyl-2,2′-bipyridine [Cu (C18H24N2) (NO3)2], 1 is investigated through its synthesis and characterization using elemental analysis technique, infra-red spectroscopy, and single-crystal analysis. The compound 1 crystallizes in orthorhombic space group P212121. The copper atom in the mononuclear complex is hexa coordinated through two nitrogen and four oxygen atoms from bipyridine ligand and nitrate ligands. The thermal analysis depicts the stability of the entitled compound up to 170 °C, and the decomposition takes place in different steps between 170 and 1000 °C. Furthermore, quantum chemical techniques are used to study optoelectronic, nonlinear optical, and therapeutic bioactivity. The values of isotropic and anisotropic linear polarizabilities of compound 1 are calculated as 41.65 × 10−24 and 23.02 × 10−24 esu, respectively. Likewise, the static hyperpolarizability is calculated as 47.92 × 10−36 esu using M06 functional compared with para-nitroaniline (p-NA) and found several times larger than p-NA. Furthermore, the antiviral potential of compound 1 is studied using molecular docking technique where intermolecular interactions are checked between the entitled compound and two crucial proteins of SARS-CoV-2 (COVID-19). Our investigation indicated that compound 1 interacts more vigorously to spike protein than main protease (MPro) due to its better binding energy of −9.60 kcal/mol compared with −9.10 kcal/mol of MPro. Our current study anticipated that the above-entitled coordination complexes could be potential candidates for optoelectronic properties and their biological activity.

Safinamide mesylate (SM), the pure active pharmaceutical ingredient (API) recently used in Parkinson disease treatment, recrystallized employing water-ethanol mixture of solvents (vol/vol 1:9) gives a different crystallographic form compared to SM in Xadago tablets. Pure SM crystallizes as a hemihydrate in the monoclinic system with the P21 space group. Its crystal and molecular structure were determined by means of cryo X-ray crystallography at 100 K. SM in the Xadago tablet exists in anhydrous form in the orthorhombic crystallographic system with the P212121 space group. The water migration and thermal processes in the crystal lattice were monitored by solid-state NMR spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. SM in Xadago in the high-humidity environment undergoes phase transformation to the P21 form which can be easily reversed just by heating up to 80 °C. For the commercial form of the API, there is also a reversible thermal transformation observed between Z' = 1 ↔ Z' = 3 crystallographic forms in the 0-20 °C temperature range. Analysis of molecular motion in the crystal lattice proves that the observed conformational polymorphism is forced by intramolecular dynamics. All above-mentioned processes were analyzed and described employing the NMR crystallography approach with the support of advanced theoretical calculations.

Acta crystallographica / B 77(6), 986 - 995 (2021). doi:10.1107/S2052520621010088, A new six-membered cyclic alkanolamine with chemical formula C$_6$H$_{15}$N$_3$O$_3$ was synthesized by the reaction of glycolaldehyde with gaseous ammonia. The molecular structure, characterized by a hexagonal ring of alternating carbon and nitro��gen atoms with three hy��droxy��methyl groups attached to the carbon atoms, could not be unambiguously determined by elemental analysis and $^1$H/$^{13}$C/$^{15}$N NMR. The molecular structure and conformation were further determined using a combination of vibrational spectroscopy (IR and Raman) and real-space pair distribution function (PDF) analysis. The crystal structure was determined ab initio from laboratory X-ray powder diffraction (XRPD) with orthorhombic space group Ama2 (No. 40) and unit-cell parameters a = 12.1054 (2) ��, b = 13.5537 (2) �� and c = 5.20741 (8) ��. Consistent structure models could be obtained by symmetry-independent PDF and PDF-Rietveld co-refinements. Independent local structure refinements indicate that the most likely deviations from the average structure consist of small tilting and translational distortions of hydrogen-bonded molecular stacks. Thermal analysis (TG/DTA) and temperature-dependent XRPD measurements were also performed to determine the thermal behavior., Published by Wiley-Blackwell, Oxford [u.a.]

For the investigation of the exchange bias effect and magneto-optical properties of Bi0.8Re0.2(Re = Nd and Sm)FeO3 (BNFO and BSFO) nanofibers were synthesized via the electrospinning technique. The crystal structure was changed from rhombohedral phases of space group R3c before undoping shift to orthorhombic phases of space group Pbam and Pnma after doping of Nd3+ and Sm3+ ions, respectively, by the Rietveld refinement results. Analysis of the magnetic hysteresis loops demonstrated that the remanent magnetization especially coercivity of BNFO and BSFO nanofibers at 10 K and 300 K exhibited obviously variation, which was attributed to the lower temperature suppressed the fluctuation of magneto-caloric and valence state. The XPS and EDS results displayed the Nd3+ and Sm3+ ions were successfully doped into BFO nanofibers. Meanwhile, the lattice distortion induced the suppression of antiferromagnetic ordered spin modulation, which played an important role to enhance the magnetic properties. It was observed that the exchange bias effect (HEB) of BNFO nanofibers was higher than those of BSFO nanofibers. UV–vis spectra measurements revealed the band gap of BNFO and BSFO nanofibers was 1.87 eV and 1.85 eV, respectively, and the absorption edges of BSFO nanofibers occurred a slightly red shift. The MO degradation rates of BNFO and BSFO nanofibers reached about 89.4% and 78.6%, respectively, which could be a potential candidate in photo-electron devices and the semiconductor industry.

A potassium salt of the N2S2O2-coordination Fe(III) anion K[Fe(5Cl-thsa)2] (1) (5Cl-thsa - 5-chlorosalicylaldehyde thiosemicarbazone) is synthesized and characterized structurally and magnetically over a wide temperature range. Two polymorphs of salt 1 characterized by the common 2D polymer nature and assigned to the same orthorhombic Pbcn space group have been identified. The molecular structure of the minor polymorph of 1 was solved and refined at 100, 250, and 300 K is shown to correspond to the LS configuration. The dominant polymorph of 1 features K+ cations disordered over a few crystallographic sites, while the minor polymorph includes fully ordered K+ cations. The major polymorph exhibits a complete three-step cooperative spin-crossover transition both in the heating and cooling modes: The first step occurs in a temperature range from 2 to 50 K; the second abrupt hysteretic step occurs from 200 to 250 K with T1/2 = 230 K and a 6 K hysteresis loop. The third gradual step occurs from 250 to 440 K. According to 57Fe Mossbauer, XRPD, and EXAFS data, the spin-crossover transition for the dominant polymorph is quite peculiar. Indeed, the increase in the HS concentration by 57% at the second step does not result in the expected significant increase in the iron(III)-ligand bond lengths. In addition, the final step of the spin conversion (ΔγHS = 26%) is associated with a structural phase transition with a symmetry lowering from the orthorhombic (Pbcn) to the monoclinic (P21/n) space group. This nontrivial phenomenon was investigated in detail by applying magnetization measurements, electron spin resonance, 57Fe Mossbauer spectroscopy, and DFT calculations. These results provide a new platform for understanding the multistep spin-crossover character in the Fe(III) thsa-complexes and related compounds.

High-purity and fine CrB powders are firstly synthesized from Cr and B powders in (Na, K)Cl molten salt at 850 °C for 2 h. Then the as-achieved CrB powders are used as precursors to synthesize homogeneous and size-controlled Cr2AlB2 powders in (Na, K)Cl molten salt at 900 °C for 2 h. Additionally, the formation mechanisms of CrB and Cr2AlB2 in (Na, K)Cl molten salt are also investigated. Results show that the Cr atom, formed by disproportionation of Cr2+ ions in molten salt, reacts in-situ with B powders to form CrB. For the formation of Cr2AlB2, Al and CrB migrate mutually and assemble firstly in the molten salt, and then Al intercalates into CrB to generate Cr2AlB2.

In this work, five substituted perovskite such as (Gd0.9Sr0.1) Mn0.8Co0.2O3, Tb0.8Sr0.2FeO3, Gd0.6Sr0.4RuO3, SrCe0.95Y0.05O3, and Mn0.6Co0.4SnO3 were synthesized by tartrate and hydroxide precursor method. The resulting samples were characterized by inductively coupled plasma spectroscopy, energy dispersive X-ray analysis, infrared spectroscopy, thermal analysis, X-ray powder diffraction, transmission electron microscope (TEM), selected field of electron diffraction (SAED), d.c. electrical conductivity, Hall effect, dielectric measurements, and low-temperature magnetization measurements. The X-ray diffraction pattern for all compounds was indicated the formation of single-phase perovskite with orthorhombic structure except Tb0.8Sr0.2FeO3 and Mn0.6Co0.4SnO3 perovskite. These compounds showed a cubic and rhombohedral structure, respectively. The lattice parameter and the unit cell volume slightly decreased as ionic radii decrease in agreement with the lanthanide contraction. The average size of cation ˂ RA ˃, mismatch factor (σ2), and tolerance factor (t) gives the combined effects of disorder and inhomogeneity in these compounds. The average particle size determined from TEM was in the range of 22 to 77 nm for all compounds. The temperature dependence of electrical conductivity for all compounds showed a definite break in 500 K to 610 K. except the Gd0.6Sr0.4RuO3 compound, which corresponds to semiconducting behavior. While the Gd0.6Sr0.4RuO3 sample shows a metallic-like semiconductor. The thermoelectric power and Hall effect measurements for all compounds were n-type semiconductivity except the SrCe0.95Y0.05O3 compound. It showed p-type semiconductivity. The frequency dependence of the dielectric constant and dielectric loss in these substituted perovskites were discussed using the Maxwell-Wagner model. Magnetic studies showed that the thermo-magnetic irreversibility for all compounds.

For the first time, AA h boron nitride (BN) crystal, assigned to an orthorhombic space group (No. 31, Pm21), is reported. The structure of BN nanotubes is reinterpreted as a helix, resulting from texture and helical growth of the AA h BN crystal used., AA h boron nitride (BN) crystal, assigned to an orthorhombic space group (No. 31, Pm21), is reported here. This new AA h BN crystal exhibits a ‘linear’ morphology for high-resolution transmission electron microscopy (HRTEM) and a (non-hexagonal) ‘diagonal’ electron-diffraction pattern, which have been experimentally demonstrated in this article. It is also demonstrated that this new crystal is the basic structure of multi-walled BN nanotubes (BNNTs) existing in the form of a helix. The helical AA h BNNTs exist in a metastable phase owing to 〈200〉 texture growth of the orthorhombic crystal, where the energy is ∼15 meV higher than that of stable AB or AA′ BN. It is shown that the typical scanning electron microscope ‘fluffy cotton-like’ morphology of BNNTs is due to secondary growth of diverse BN sheets (including mono-layers) on incoherently scrolled wall strands of BNNTs, providing further evidence for the helical structure with HRTEM evidence for a left-handed helix.

(Cu0.5Tl0.5)(Ba2–yCay)(CaMg)(Cu3–xZnx)O10–δ (y = 0, 1; x = 0, 2, 2.5, 2.8, 3) and (MxTl1–x)(BaCa)(CaMg) Zn3O10–δ (M = Ag, K; x = 0, 0.5) superconductors are synthesized for the studies of role of spin density waves in the mechanism of high Tc superconductivity. Such compounds are synthesized by reducing the thickness of the charge reservoir layers and distance among various CuO2/ZnO2 planes; decreasing the thickness of charge reservoir layers (CRLs) and distance among the various CuO2/ZnO2 planes increase the spin–spin interaction. All such samples were prepared by a two-step solid-state reaction (SSR) method at 860 °C and have shown orthorhombic crystal structure in which volume (V) of the unit cell suppresses with the doping of Ca, showing that partial substitution of Ca at the Ba site suppresses the thickness of CRL that in turn promotes a decrease in c-axis length and volume of the unit cell. The phonon modes related to the vibrations of apical and planar oxygen atoms are softened with doping of Ca and Zn in the final compounds. Metallic variations of resistivity (ρ) from room temperature down to the onset of superconductivity are a typical feature of these samples in which the Tc(onset) and Tc(R = 0) suppress with the doping of Ca, Mg, and Zn in the final compounds. Surprisingly, the samples with all the CuO2 planes replaced by ZnO2 planes have shown superconducting properties. To confirm the role of Cu(3d9) atoms in superconductivity, we have synthesized (MxTl1–x)(BaCa)(CaMg) Zn3O10–δ (M = Ag, K; x = 0, 0.5) samples. To our surprise, such samples have shown semiconducting behavior and no sign of superconductivity down to 77 K which demonstrated that the presence of Cu(3d9) atoms either in CRLs or ZnO2 planes is essential for the mechanism of high Tc superconductivity. These studies have shown the unequivocal role of small spin-carrying Cu-atoms in the mechanism of high Tc superconductivity. Fluctuating spins of Cu(3d9) atoms in the CuO2 plane generate spin waves, and hence, their interaction with charge density waves develop long-range phase coherence among the carriers that result in high-temperature superconductivity in oxides.

Layered oxyhalides containing double or triple fluorite layers are promising visible-light-responsive water-splitting photocatalysts with unique band structures. Herein, we report on the synthesis, structure, and photocatalytic property of Bi4BaO6Cl2 (I4/mmm) with alternating double (Bi2O2) and triple (Bi2BaO4) fluorite layers, which was extracted from the crystallographic database on the basis of Madelung potential calculations. Rietveld refinements from powder X-ray and neutron diffraction data revealed the presence of cationic disorder between Bi2O2 and Bi2BaO4 layers, leading to electrostatic stabilization. DFT calculations suggested that photogenerated electrons and holes flow through the double and triple layers, respectively, which may suppress electron-hole recombination. We expanded this double-triple system to include Bi4CaO6Cl2 and Bi4SrO6Cl2 with orthorhombic distortions and different degrees of cationic disorder, which allow band gap tuning. All the double-triple compounds Bi4AO6Cl2 showed stable water-splitting photocatalysis in the presence of a sacrificial reagent.

The structure of a binuclear niobium(IV) thiocyanate complex (Bu4N)4[Nb2(μ2-S2)2(NCS)8]·H2O (1·H2O) is studied by X-ray crystallography. Compound 1·H2O crystallizes in the orthorhombic crystal system (space group Pbca) with unit cell parameters a = 23.2139(4) A, b = 25.2962(4) A, с = 32.5478(6) A, V = 19112.8(6) A3, R = 0.0592. The electronic structures of (Bu4N)4[Nb2(μ2-S2)2(NCS)8] and (Bu4N)4[Nb2(μ2-Se2)2(NCS)8] complexes are investigated by X-ray spectroscopy techniques and compared with the structures of polymeric chalcogenides Nb2S4Br4 and Nb2Se4Br4. By XPS it is shown that effective charges on atoms of the {Nb2(μ-Q2)2}4+ (Q = S, Se) core do not change when passing from Br– to NCS– ligands. The HOMO and LUMO structures of (Bu4N)4[Nb2(μ2-S2)2(NCS)8] and (Bu4N)4[Nb2(μ2-Se2)2(NCS)8] are analyzed by XPS and XANES techniques. The largest contributions of S 3p states of NCS– ligands to the occupied molecular orbitals are found to be near the upper boundary of the valence band while the contributions from dichalcogenide bridging ligands have a more uniform distribution. For the conduction band, the contributions of S 3p states of NCS– ligands are located deeper whereas the contributions from dichalcogenide bridging ligands are near the lower boundary of the conduction band. The interaction of Nb 4d and S 3p/Se 4p states of dichalcogenide bridges for the HOMO has an antibonding character, which is bonding for all the other occupied molecular orbitals and antibonding for all unoccupied molecular orbitals.

The quaternary selenide Ba4GeSb2Se11 was prepared by a high-temperature solid state reaction method. Ba4GeSb2Se11 crystallizes in an acentric orthorhombic space group Cmc21 with the lattice constants a = 9.370(11) A, b = 25.850(0) A, and c = 8.798(10) A. The compound is composed of a [SbSe3]3- trigonal pyramid, [GeSbSe5]3- dimers, V-shaped Se32-, and the adjacent Ba2+ ions. It has indirect band gap of 1.35 eV and exhibits a second harmonic generation intensity of about 0.2 times that of the benchmark compound AgGaS2 at the same particle size. Interestingly, theoretical analyses show that the central Se atom of Se32- has the largest contribution (8.1%) to d31 compared to that of other Se atoms, which may be due to its easy swing in the a-axis direction.

We provide the material synthesis method, crystal structure information, and characterization of a novel mixed-valent metal oxide KIn0.33IIITe0.67VITe2IVO7, closely related to zirconolite (CaZrTi2O7), a radioactive waste immobilized material, having a 3D framework. The reported metal oxide containing an alkali-metal cation (K+), main-group cation (In3+), tellurate, and tellurite has been synthesized as both single crystals and a pure polycrystalline phase through a hydrothermal synthesis method. Single-crystal X-ray diffraction indicates that KIn0.33Te2.67O7 crystallizing in the orthorhombic space group Cmcm (No. 63) reveals a 3D framework structure with a 1D channel consisting of Te/InO6 octahedra and TeO4 polyhedra. An interesting transition reaction from KIn0.33Te2.67O7 to KIn(TeO3)2 under hydrothermal conditions at 230 °C is discussed.

The crystal and electronic structure properties of Ni-B (nickel-boron) alloy coatings produced by an electrodeposition method have been investigated. The crystal structures of the alloy coatings were determined by x-ray diffraction patterns and supported by extended x-ray absorption fine structure (EXAFS) spectroscopy. The local atomic structure around the Ni atom was obtained from EXAFS studies at the Ni K-edge, and the EXAFS data were fitted with theoretical calculations. With the addition of boron atoms in the nickel environment, NiB composite alloys were formed in the crystals with an orthorhombic "Cmcm" structure. The analysis revealed a limited effect of boron doping in the electronic structure of the nickel atoms. Boron atoms were determined as sitting between the Ni atoms and causing a disturbance in the crystal structure due to providing inhomogeneous interstitial potential and defects.

Two alkali tin(II) phosphates, namely, Rb[SnF(HPO4)] and Rb(Sn3O)2(PO4)3, were synthesized through mild hydrothermal methods. They belong to the orthorhombic Pnma and Pbcn space groups, respectively. Rb[SnF(HPO4)] features a layered structure based on 1D [SnF(HPO4)]∞ chains interconnected by hydrogen bonds, with Rb+ cations located at the interlayer space. For Rb(Sn3O)2(PO4)3, each pair of [Sn3O]4+ clusters is bridged by a pair of [P(1)O4]3- tetrahedra to build a 1D [Sn-P-O]∞ chain. These 1D [Sn-P-O]∞ chains are further cross-linked though [P(2)O4]3- tetrahedra to construct a 3D network with 7- and 10-membered-ring channels. The tin(II) ions in Rb[SnF(HPO4)] and Rb(Sn3O)2(PO4)3 with stereochemically active lone pairs (SCALPs) significantly enhance the birefringences of metal phosphates: Δn = 0.147@1064 nm for Rb[SnF(HPO4)] and 0.082@1064 nm for Rb(Sn3O)2(PO4)3.

Eleven examples of hexagonal and orthorhombic polymorphs of intermetallic compounds having 5:3 stoichiometry are listed in the International Crystal Structure Database. A transition temperature between them has only been determined for the Yb–Sb and Sr–Bi systems, but results on the Sr–Bi system are discrepant with those on the Yb–Sb system, in which the phase relationships are well constrained by experimental data, for example, that the lower-temperature polymorph is the prototype orthorhombic Yb5Sb3 structure (αY5Sb3) and the higher temperature polymorph (βYb5Sb3) is isostructural with hexagonal Mn5Si3, with the transformation occurring at 1280 °C. In contrast, thermodynamic modeling on the Sr–Bi system give the inverse sequence of polymorphs with increasing temperature. It appears unlikely that the hexagonal Mn5Si3 structure type can be stable at higher temperatures than the orthorhombic Yb5Sb3 structure in one system, while orthorhombic Yb5Sb3 structure is the stable phase at higher temperatures in another system. The discrepancy can be attributed to the limited experimental data used to model the phase relationships in the Sr–Bi system.

The present article is focused to probe guanidinium benzene-1,2-dicarboxylate (GUBD) crystal synthesized by slow evaporation technique. The synthesized material possesses centrosymmetric structure with Pbcn space group having orthorhombic crystal system. The inter-contacts of the synthesized material have been investigated using Hirshfeld surface analysis and it clearly visualizes that the intermolecular hydrogen bonding takes place for structural stabilization. The functional groups of synthesized material have been affirmed from FT-IR and FT-Raman spectra. GUBD possess cut-off edge at 250 and 272 nm with high optical transparency in the visible-NIR region. The T/G and DTA show studied compound is thermally stable up to 300 °C. The observation of maximum intensity peak for the GUBD crystal at 570 nm pointed out green fluorescence emission. The Vicker’s hardness analysis reveals reverse indentation size effect. Dielectric studies of the GUBD crystal were measured. The nonlinear optical measurements on GUBD material confirm the two-photon absorption with reverse saturable absorption behavior and the crystal is potentially sufficient for optical limiting-based laser safety devices. The antibacterial activities of GUBD crystal against strains Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus have been analyzed. Furthermore, the grown GUBD crystal finds potential application in the field of electro-optic device and pharmaceutical applications.

In this work, nanowires and nanorods of WOx have been synthesized by the solvothermal method. The effect of reaction time and acetic acid as solvent were studied. X-ray diffraction (XRD) patterns showed the monoclinic WO2.72, WO2.79, and orthorhombic WO3 crystalline structures. Scanning Electron Microscopy (SEM) and High-Resolution Transmission Electronic Microscopy (HRTEM) images presented nanostructures such as nanowires and nanorods at different sizes. Band gap energies were supplied by Ultra Violet visible (UV-vis) absorption spectra. The Photoluminescence (PL) spectra exhibited three emission peaks in the blue zone at 440, 460, and 484 nm. X-ray Photoelectron Spectroscopy (XPS) was used to calculate W6+, W5+, and W4+ oxidation states. The results showed that increasing the reaction time from 10 h to 24 h affected the crystalline structure from monoclinic to orthorhombic. Moreover, with the addition of acetic acid as solvent, the crystal structure is not affected but stabilizes the monoclinic phase in the course of time.

Demands for IR birefringent materials are increasing due to the rapid developments of IR laser applications. Herein, two new chain tellurides β-BaGa2Te4 and Ba5Ga2Ge3Te12 have been discovered. β-BaGa2Te4 crystallizes in the orthorhombic space group Imma (no. 74) with unit cell constants of a = 23.813(3) A, b = 11.9673(19) A, and c = 6.7215(9) A, while Ba5Ga2Ge3Te12 crystallizes in the monoclinic space group P21/c (no. 14) with unit cell constants of a = 13.6540(3) A, b = 9.6705(2) A, and c = 23.1134(7) A. The structure of β-BaGa2Te4 can be considered to be the antiparallel arrangement of one-dimensional (1D) [GaTe2] chains formed by edge-sharing GaTe4 tetrahedra, which are separated by Ba2+ cations. In the crystal structure of Ba5Ga2Ge3Te12, two kinds of 1D chains, namely chain 1 ∞1[(GaGe)3Te8] and chain 2 ∞1[(GaGe)2Te4], are stacked alternately and put together by the coulomb force with Ba2+ cations. In addition, First-principles calculations indicate that β-BaGa2Te4 has a large birefringence, ∼0.325 at 2050 nm, derived from the superposition of the polarizabilities of GaTe4 tetrahedra, implying that it has potential as an IR birefringent material. This work may provide some guidance for exploring new IR birefringent crystals.

International audience; A new salt Bis(o-xylylenediammonium) tetrachloride monohydrate, denoted by OXDACl, produces a novel organic-inorganic compound with centrosymmetric property, prepared by slow evaporation technique in an aqueous solution. This one has been assumed a pattern in the orthorhombic Pnma space group, and the following crystallographic parameters obtained are a = 9.0677(9) angstrom, b = 24.282 (2) angstrom, c = 9.4726 (8) angstrom, V = 2085.7 (3)angstrom(3) and Z = 4, at 150 K. It is investigated by X-ray diffraction, fluorescence, infrared, and UV-visible spectroscopy. The crystal wrap is endorsed by the O-H center dot center dot center dot Cl, N-H center dot center dot center dot Cl hydrogen bond interactions among the organic network and the inorganic one, which stabilize the crystal packing. Besides to get a perception into the attitude of these interconnections, Hirshfeld surfaces analysis have been scrutinized. Computational calculations were performed, employing density functional theory (DFT), and were made by comparison with the experimentally determined structure to examine the molecular structure with geometrical optimization, vibrational, and topological parameters of OXDACl by B3LYP/6-311 + + G(d,p) basis.

We have synthesized the orthocarbonate Sr3[CO4]O in a laser-heated diamond anvil cell at 20 and 30 GPa by heating to ≈3000 (300) K. Afterward, we recovered the orthocarbonate with [CO4]4- groups at ambient conditions. Single-crystal diffraction shows the presence of [CO4]4- groups, i.e., sp3-hybridized carbon tetrahedrally coordinated by covalently bound oxygen atoms. The [CO4]4- tetrahedra are located in a cage formed by corner-sharing OSr6 octahedra, i.e., octahedra with oxygen as a central ion, forming an antiperovskite-type structure. At high pressures, the octahedra are nearly ideal and slightly rotated. The high-pressure phase is tetragonal (I4/mcm). Upon pressure release, there is a phase transition with a symmetry lowering to an orthorhombic phase (Pnma), where the octahedra tilt and deform slightly.

Effects of Ga substitutions in R2Al1-xGax (R = Gd, Er) alloys have been studied. Gd2Al1-xGax (x ≤ 0.2) and Er2Al1-yGay (y ≤ 0.3) alloys are found to be crystallized in Co2Si-type orthorhombic structure. With increased Ga substitution for Al, the phase transition temperature is gradually increased. For the field change of 7 T, the maximum of entropy change (-ΔSM) is increased to 14.8 J/kgK and 11.2 J/kgK in Gd2Al0.8Ga0.2 and Er2Al0.7Ga0.3 alloys compared with 11.4 J/kgK and 8.3 J/kgK of Gd2Al and Er2Al alloys. And the relative cooling power is nearly doubled to 699.6 J/kg in Gd2Al0.8Ga0.2 alloy. As increasing Ga substitution, the critical magnetic field for the transition is decreased in Gd2Al1-xGax (x ≤ 0.2) alloys, and the magnetization is increased in Er2Al1-yGay (y ≤ 0.3) alloys. The considerable ΔSM implies that those materials are promising candidates for magnetic cooling.

The novel α-BaZn2P2 structural polymorph has been synthesized and structurally characterized for the first time. Its structure, elucidated from single crystal X-ray diffraction, indicates that the compound crystallizes in the orthorhombic α-BaCu2S2 structure type, with unit cell parameters a = 9.7567(14) A, b = 4.1266(6) A, and c = 10.6000(15) A. With β-BaZn2P2 being previously identified as belonging to the ThCr2Si2 family and with the precedent of structural phase transitions between the α-BaCu2S2 type and the ThCr2Si2 type, the potential for the pattern to be extended to the two different structural forms of BaZn2P2 was explored. Thermal analysis suggests that a first-order phase transition occurs at ∼1123 K, whereby the low-temperature orthorhombic α-phase transforms to a high-temperature tetragonal β-BaZn2P2, the structure of which was also studied and confirmed by single-crystal X-ray diffraction. Preliminary transport properties and band structure calculations indicate that α-BaZn2P2 is a p-type, narrow-gap semiconductor with a direct bandgap of 0.5 eV, which is an order of magnitude lower than the calculated indirect bandgap for the β-BaZn2P2 phase. The Seebeck coefficient, S(T), for the material increases steadily from the room temperature value of 119 μV/K to 184 μV/K at 600 K. The electrical resistivity (ρ) of α-BaZn2P2 is relatively high, on the order of 40 mΩ·cm, and the ρ(T) dependence shows gradual decrease upon heating. Such behavior is comparable to those of the typical semimetals or degenerate semiconductors.

A new pyrophosphate(V) of the formula Co5Cr2(P2O7)4 was obtained in the system Co2P2O7–Cr4(P2O7)3 as a result of solid-state reactions taking place between different reactants. The new compound crystallizes in the orthorhombic system and belongs to the family of pyrophosphates of the general formula M52+M23+(P2O7)4 and is probably isostructural with Fe52+Fe23+(P2O7)4. Powder diffraction pattern, infrared spectrum and SEM image of the new compound were presented. As a new potential inorganic pigment, Co5Cr2(P2O7)4 was tested for its thermal stability, particle size distribution and colour properties, which were studied both for powder and after introduction into organic matrix and leadless ceramic glaze. The colour of Co5Cr2(P2O7)4 powder was defined as deep grey with the colour coordinates L*/a*/b* = 60.63/-1.42/-3.41 and according to the hue angle (h° = 247.39°) it belongs to the blue region. Co5Cr2(P2O7)4, with its relatively high thermal stability (t m = 1230 ± 10 °C) and appropriate colour properties, is a good candidate to be used as inorganic pigment for colouring of acrylic paints. In the case of leadless glaze, the obtained compound acts as a dye.

Microwave-assisted synthesis of N-methyl-2,3-diferrocenyl-4,4-dicyanopyrrolidine has been accomplished in moderate yields via a facile 1,3-dipolar cycloaddition and its crystal structure was determined by single-crystal X-ray diffraction (CCDC no. 1583719). It crystallizes: C27H25Fe2N3, Mr = 503.20, orthorhombic, P212121, a = 10.4873(9), b = 10.5251(10), c = 20.8587(19) A, V = 2302.4(4) A3, ρ = 1.452 g cm−3, Z = 4, T = 298(2) K.

To study the cyclopentane sorption sites and the effect of sorption on the H-ZSM-5 structure, crystal of H-ZSM-5 were prepared by burning out the tetrapropylammonium cations in air. For the adsorption of cyclopentane into H-ZSM-5 crystal, the crystal was treated with zeolitically dried cyclopentane for 6 h at 297 K, and then evacuated for 600 s at this temperature and 1.1 × 10–4 Pa. The structure of a single crystal of cyclopentane sorption complex of dehydrated H-ZSM-5 (MFI, |H3.8(C5H10)1.47|[Al3.8Si92.2O192]-MFI, Si/Al = 24) has been determined crystallographically using synchrotron X-radiation in the orthorhombic space group Pnma; a = 20.141(4), b = 19.944(4), c = 13.439(3) A. It was refined using all intensities to the final error indice R1 = 0.072. The 1.47 cyclopentane molecules per unit cell are located between 5-rings in zigzag channel. The cyclopentane molecules are located perpendicular to the 10-rings of zigzag channel and parallel to the 5-rings of H-ZSM-5 framework at the center of them. Each cyclopentane molecule is held in place by 16 hydrogen bonds between all hydrogen atoms of cyclopentane and framework oxygen atoms of its 5- and 10-rings: C···O ca. 3.318 ~ 3.992 A.

Hydrothermally synthesised K2ZnSi5O12 has a polymerised framework structure with the same topology as leucite (KAlSi2O6, tetragonal I41/a), which has two tetrahedrally coordinated Al3+ cations replaced by Zn2+ and Si4+. At 293 K it has a cation-ordered framework P21/c monoclinic structure with lattice parameters a = 13.1773(2) Å, b = 13.6106(2) Å, c = 13.0248(2) Å and β = 91.6981(9)°. This structure is isostructural with K2MgSi5O12, the first cation-ordered leucite analogue characterised. With increasing temperature, the P21/c structure transforms reversibly to cation-ordered framework orthorhombic Pbca. This transition takes place over the temperature range 848−863 K where both phases coexist; there is an ~1.2% increase in unit cell volume between 843 K (P21/c) and 868 K (Pbca), characteristic of a first-order, displacive, ferroelastic phase transition. Spontaneous strain analysis defines the symmetry- and non-symmetry related changes and shows that the mechanism is weakly first order; the two-phase region is consistent with the mechanism being a strain-related martensitic transition.

La estructura cristalina del compuesto ácido 2-E-((4-hidroxifenil) diazenil) benzóico se resolvió por medio del método de fase intrínseca usando datos de difracción de rayos X de monocristal, encontrando que la molécula cristaliza en el sistema cristalino ortorrómbico con grupo espacial Pbca. Dentro de su celda unidad hay cuatro moléculas por unidad asimétrica que son confórmeros moleculares. Estos confórmeros forman hélices beta a lo largo de la dirección [010]. A partir de los datos estructurales se realizó el cálculo de superficies de Hirshfeld determinando, a partir de ellas, sus correspondientes diagramas de huellas dactilares bidimensionales, lo que permitió estudiar las interacciones intermoleculares que más contribuyen al empaquetamiento cristalino. Así, se pudo determinar que la principal contribución a la superficie general está dada por los contactos H···H (34,8%), seguida de interacciones O···H/H···O (27%) y C···H/H···C (18,6%). También fueron calculadas las redes energéticas de interacción con un nivel de teoría DFT/B3LYP/6-31G(d,p), permitiendo cuantificar los valores de cada componente que aportan a la energía total, siendo las interacciones de dispersión (-57,5 kJ/mol) las que más contribuyen en la formación del empaquetamiento cristalino para este compuesto.

We synthesized single crystals of marokite (CaMn2O4)-type orthorhombic manganese (II,III) oxide, γ-Mn3O4, in a multianvil apparatus at pressures of 10-24 GPa. The magnetic, electronic, and optical properties of the crystals were investigated at ambient pressure. It was found that γ-Mn3O4 is a semiconductor with an indirect band gap Eg of 0.96 eV and two antiferromagnetic transitions (TN) at ∼200 and ∼55 K. The phase stability of the γ-Mn3O4 crystals was examined in the pressure range of 0-60 GPa using single-crystal X-ray diffraction and Raman spectroscopy. A bulk modulus of γ-Mn3O4 was determined to be B0 = 235.3(2) GPa with B' = 2.6(6). The γ-Mn3O4 phase persisted over the whole pressure range studied and did not transform or decompose upon laser heating of the sample to ∼3500 K at 60 GPa. This result seems surprising, given the high-pressure structural diversity of iron oxides with similar stoichiometries. With an increase in pressure, the degree of distortion of MnO6 polyhedra decreased. Furthermore, there are signs indicating a limited charge transfer between the Mn3+ ions in the octahedra and the Mn2+ ions in the trigonal prisms. Our results demonstrate that the high-pressure behavior of the structural, electronic, and chemical properties of manganese oxides strongly differs from that of iron oxides with similar stoichiometries.

Three new alkali-metal manganese fluoride selenates, A2Mn(SeO4)F3 (A = K, Rb, Cs), were prepared through hydrothermal redox reactions. The products consisted of one-dimensional polymeric anionic ∞[Mn(SeO4)F3]2- chains, where the A+ cations are connected by O and/or F atoms to form blocks with two-dimensional layers. A2Mn(SeO4)F3 (A= Rb, Cs) is isostructural with the monoclinic space group P21/c, while K2Mn(SeO4)F3 crystallizes in the orthorhombic space group Pbcn. A2Mn(SeO4)F3 (A = K, Rb, Cs) forms spin chains of Mn3+ with different Mn-F-Mn bridges, which showed canting antiferromagnetic behaviors. Single-crystal magnetic measurements revealed that the magnetic moments of the Mn ions were more canted for larger alkali-metal compounds in an antiferromagnetically ordered state.

International audience; SrREGa3O7 melilite ceramics with large rare-earth elements (RE = La to Y) are famous materials especially known for their luminescence properties. Using an innovative approach, the full and congruent crystallization from glass process, SrREGa3O7 transparent polycrystalline ceramics with small rare earth elements (RE = Dy-Lu and Y) have been successfully synthesized and characterized. Interestingly, compared to the classic tetragonal (P-421m) melilite structure composed of mixed Sr/RE cationic sites, these compositions can crystallize in a 3 x 1 x 1 orthorhombic (P21212) superstructure. A detailed study of the superstructure, investigated by different techniques (synchrotron and neutron powder diffraction, STEM-HAADF imaging and EDS mapping), highlights the existence of a Sr/RE cation ordering favored by a large Sr/RE size mismatch and a sufficiently small RE cation. An appropriate control of the synthesis conditions through glass crystallization enables the formation of the desired polymorphs, either ordered or disordered. The influence of this tailored cationic ordering/disordering on the RE luminescent spectroscopic properties have been investigated. A stronger structuration of the RE emission band is observed in the ordered ceramic compared to the disordered ceramic and the glass, whose band shapes are very similar, indicating that the RE environment in the glass and disordered ceramic are close.

This paper reports the effect of chromium’s substitution in magnetic oxides with perovskite structure La0.5Sm0.2Sr0.3Mn1-xCrxO3 (x = 0, 0.1, 0.15 and 0.2) compounds which have been produced with the glycine-nitrate process (GNP). The four compounds have an orthorhombic crystal structure with ‘Pnma’ space group. We note that they undergo a second-order paramagnetic-ferromagnetic (PM-FM) phase transition. Substitution manganese by chromium leads to a drop of the Curie temperature TC from 278 K (x = 0) to 205 K (x = 0.2). Their magnetocaloric effect has been evaluated by their magnetic entropy change $$\left(-\Delta {S}_{M}^{max}\right)$$ under a magnetic field change up to 5 T. All relative cooling power (RCP) suggests that these compounds are suitable candidates for magnetic refrigeration.

The effect of Nb on the crystal structures and electronic mechanism of martensitic transformation in Ni50Ti50-x Nb x alloys is investigated by first principles. The lattice parameters, the formation energy, the middle eigenvalue of the transformation stretch tensor (λ2), and the energy difference between the parent and martensite (ΔE) as a function of Nb content x (x = 0, 2.08, 6.25, 8.33, 10.42, 12.5, 18.75) are calculated. Lattice parameters increase with the increase of Nb content. The formation energies of the parent B2 phase, martensite orthorhombic B19, and monoclinic B19' increase with the increase of Nb content. It is also found that at ≤10.42 at. % Nb, the martensite stable phase is monoclinic structure B19'; at >10.42 at. % Nb, the orthorhombic crystal structure B19 is formed. The energy difference between the parent and martensite means that the transformation temperature decreases with increasing Nb concentration at Nb ≤ 10.42 at. % and increases at >10.42 at. % Nb. The λ2 of the NiTiNb alloys have the same value of about 0.95 with low Nb content. Furthermore, the electronic structure mechanisms behind the martensitic transformations are discussed in detail based on the density of states.

A plasma-based undoped-HfO2 FeFET (ferroelectric FET) with non-volatile memory characteristics is demonstrated. Modifying the O2 plasma period in plasma-enhanced atomic layer deposition (PE-ALD) is an effective approach to enhance the remnant polarization ( $\text{P}_{\text {r}}$ ) up to 2P $_{\text {r}} = 25\,\,\mu \text{C}$ /cm2 for the MFM (metal/ferroelectric/metal) structure with ferroelectric undoped-HfO2 thin films, and successful integration is implemented for the FeFET. The appropriate O2 vacancies ( $\text{V}_{\text {o}}^{{2}+}$ ) benefit the formation of the ferroelectric phase since they play the role of dopants and help orthorhombic phase (o-phase) formation during post-metal annealing (PMA). The $\text{V}_{\text {o}}^{{2}+}$ -rich undoped-HfO2 FeFET exhibits a memory window (MW) of 0.5 V, ${5} \times {10}^{{4}}$ switching endurance cycles, and higher than $10^{{4}}$ sec of data retention with $\text{V}_{\text {P/E}} = \pm 5$ V.

A novel decavanadate salt Mg(H2O)6(C6H14N2)2V10O28·8H2O is obtained by the reaction of vanadium oxide and 1,4-diazabicyclo [2.2.2] octane (DABCO). The title compound is characterized by infrared (IR) spectroscopy and powder X-ray diffraction (XRD). The spectroscopic characterization confirms the presence of the different groups in the structure. Powder XRD confirms the purity of the phase. Optical properties are recorded at room temperature using UV-Visible spectroscopy in the spectral range of 250-800 nm. According to the single crystal XRD analysis, the structure of the compound is orthorhombic: a = 17.927(6) A, b = 15.798(6) A, c = 15.723(5) A, V = 4452.8(7) A3, and Z = 4. The formula unit of Mg(H2O)6(C6H14N2)2V10O288H2O is formed by a decavanadate group, the $$\text{Mg(}{{\text{H}}_{2}}\text{O)}_{6}^{2+}$$ polyhedron, two organic (C6H14N2)2+ cations, and eight water molecules. In the crystal, molecules are linked by O–H…O and N–H…O hydrogen bonds, forming a three-dimensional network.

Recently, single-crystals of tin selenide (SnSe) have drawn immense attention in the field of thermoelectrics due to their anisotropic layered crystal structure and ultra-low lattice thermal conductivity. Layered SnSe has an orthorhombic crystal structure (Pnma) at ambient conditions. However, the cubic rock-salt phase (Fm3̄m) of SnSe can only be stabilized at very high pressure and thus, the experimental realization of the cubic phase remains elusive. Herein, we have successfully stabilized the high-pressure cubic rock-salt phase of SnSe by alloying with AgBiSe2 (0.30 ≤ x ≤ 0.80) at ambient temperature and pressure. The orthorhombic polycrystalline phase is stable in (SnSe)1−x(AgBiSe2)x in the composition range of 0.00 ≤ x < 0.28, which corresponds to narrow band gap semiconductors, whereas the band gap closes upon increasing the concentration of AgBiSe2 (0.30 ≤ x < 0.70) leading to the cubic rock-salt structure. We confirmed the stabilization of the cubic structure at x = 0.30 and associated changes in the electronic structure using first-principles theoretical calculations. The pristine cubic SnSe exhibited the topological crystalline insulator (TCI) quantum phase, but the cubic (SnSe)1−x(AgBiSe2)x (x = 0.33) showed a semi-metallic electronic structure with overlapping conduction and valence bands. The cubic polycrystalline (SnSe)1−x(AgBiSe2)x (x = 0.30) sample showed n-type conduction at room temperature, while the orthorhombic (SnSe)1−x(AgBiSe2)x (0.00 ≤ x < 0.28) samples retained p-type character. Thus, by optimizing the electronic structure and the thermoelectric properties of polycrystalline SnSe, a high zT of 1.3 at 823 K has been achieved in (SnSe)0.78(AgBiSe2)0.22., AgBiSe2 alloying in SnSe tailors its crystal and electronic structures, which boost its thermoelectric figure of merit to 1.3.