Search

Crown ether anchored organic‐inorganic hybrid halides have been recently reported as interesting luminescent materials in the visible region of electromagnetic spectrum. Is it possible to develop such crown ether anchored hybrid materials for near infrared emission? Motivated by this question, we designed a new hybrid material, namely, [(18‐Crown‐6)K][MoOCl4(H2O)]. 18‐Crown‐6 ether bound with K+ form the cationic part [(18‐Crown‐6)K]+. The K+ of [(18‐Crown‐6)K]+ electrostatically interacts with Cl− of the anionic part [MoOCl4(H2O)]−, forming the hybrid crystal [(18‐Crown‐6)K][MoOCl4(H2O)]. It crystallizes in orthorhombic crystal system with Pnma space group. The Mo(V) possesses one d‐electron (d1) in C4v ${{C}_{4v}}$ point group symmetry in the [MoOCl4(H2O)]− polyhedra. This electronic configuration leads to multiple spin‐allowed d-d ${d-d}$ transitions along with a ligand to metal charge transfer (LMCT) resulting into multiple optical absorption bands in the near UV‐visible‐near infrared (NIR) region. The lowest energy d-d ${d-d}$ transition via 2E (dxz1 ${{d}_{xz}^{1}}$ , dyz ${{d}_{yz}}$)/2E (dxz,dyz1 ${{d}_{xz},{d}_{yz}^{1}}$)→ ${\to }$ 2B2 (dxy1 ${{d}_{xy}^{1}}$) leads to NIR PL with peak at 952 nm, but with a poor intensity at room temperature. [ABSTRACT FROM AUTHOR]

Organic‐inorganic metal halide single crystals have attracted a lot of attention due to their flexible structural design and excellent optoelectronic applications. This study details the synthesis of copper‐based [(CH3)4N]2CuBr4 hybrid metal halide single crystals via a slow evaporation method. The crystal structure, crystal habit, chemical groups, intermolecular interactions, electrical properties of the sample were studied via single crystal x‐ray diffraction, scanning electron microscopy, Raman and Fourier transform infrared spectrometer, Hirshfeld surface analysis, impedance spectroscopy, and modulus spectroscopy, respectively. An orthorhombic crystal system with the non‐centrosymmetric space group Pna21 was identified at room temperature. The deformation in the tetrahedra was calculated by the bond angle and bond length deformation index. The Cole‐Cole plot displayed the existence of depressed semicircles, which indicated the predominant distribution of grains, further confirmed by the SEM image. The deformed semi‐circular arcs on the electric modulus curve undeniably prove that the bulk effect dominates the material's electrical properties. Significantly, the compound presents a phase transition at ~240 K and excellent thermal stability up to a temperature of 400 K. Therefore, our research sheds light on the temperature dependence of electrical responses in these hybrid crystals and gives inspiration for the development of single crystal‐based efficient energy devices. [ABSTRACT FROM AUTHOR]

A novel series of 1 : 1 cocrystals of 2‐cyanoguanidinophenytoin (CNG‐DPH) with primary, secondary, and tertiary aliphatic amines has been presented through this work. The antimicrobial activities of all new CNG‐DPH‐amine cocrystals were studied. The existence of cocrystals has been proven through crystal structure results. The 5‐Oxo‐4,4‐diphenylimidazolidin‐2‐ylidenecyanamide‐piperidine cocrystal (10) is located in an orthorhombic crystal system, and the cocrystal is connected via the N−H−N hydrogen bond between the cyanide group and the piperidine molecule. Hirshfeld surface analysis authenticated supramolecular contacts. Ring puckering analysis revealed a chair stereochemistry at the 6‐membered piperidine. The crystal packing has been stabilized through intermolecular forces, hydrogen bonds, and interactions within the gravity center of rings (Cg). The antimicrobial activities of the newly synthesized compounds were only effective against Gram‐positive bacteria, demonstrating that the antibacterial spectrum of these compounds was restricted. In vitro cytotoxicity of the synthesized cocrystals was assessed in normal cells, giving the highest half‐maximal inhibitory concentration (IC50) ratio (637.63 μg/ml) and the lowest value (181.98 μg/ml). [ABSTRACT FROM AUTHOR]

In the present work, we report on the synthesis of EuSO4 powders by two different methods using EuS as starting material. The compound EuSO4 contains divalent europium and crystallizes in the orthorhombic crystal system, space group Pnma with parameters close to SrSO4. The compound exhibits near isotropic thermal expansion over the temperature range 300–700 K. EuSO4 was examined by Raman, Fourier‐transform infrared absorption and luminescence spectroscopy methods. EuSO4 is found to be an indirect bandgap material with a bandgap close to direct electronic transition. The emission lifetime of divalent europium d‐f emission in EuSO4 shows an unusual behavior for stoichiometric compounds, as it shortens upon cooling from 1.11(1) μs at room temperature to 0.44(1) μs at 77 K. [ABSTRACT FROM AUTHOR]

Marijuana and hemp represent two broad classes of Cannabis sativa plants that are distinguished based on the concentration of the psychoactive cannabinoid delta‐9‐tetrahydrocannabinol (Δ9‐THC). In this work, solvent extracts derived from marijuana and hemp were characterized using optical and spectroscopic techniques. The crystalline components of the solvent extracts were first analyzed using polarized light microscopy to determine optical properties, namely, crystal system, optical sign, and principle refractive indices. Crystals from the marijuana‐derived extracts exhibited an orthorhombic crystal system and were optically negative, with nβ between 1.6320 and 1.6330 ± 0.0002. In contrast, crystals from hemp‐derived extracts exhibited a monoclinic crystal system and were optically positive, with nβ between 1.600 and 1.6040 ± 0.0002. Crystals were further distinguished through infrared spectroscopy, which highlighted structural differences between the two sample types, primarily based on differences in O‐H stretching. Finally, single‐crystal X‐ray diffraction was used to definitively identify the crystalline components, confirming the presence of tetrahydrocannabinolic acid in marijuana‐derived extracts and cannabidiol in hemp‐derived extracts. Given the differences in crystal structure identified between marijuana‐derived and hemp‐derived solvent extracts, optical characterization provides a screening method to differentiate visually similar samples prior to confirmatory analysis. [ABSTRACT FROM AUTHOR]

Polymorphism of 1,1‐diamino‐2,2‐dinitroethene (FOX‐7, DADNE) has investigated by X‐ray powder diffraction (XRD), differential scanning calorimetry (DSC), thermo gravimetric analysis (TGA), IR‐spectroscopy. Two previously unknown polymorph modifications of FOX‐7 ‐ ϵ and ζ were discovered. ϵ‐FOX‐7 has prepared by hydrolysis of 2‐(dinitromethylene)‐5,5‐dinitropyrimidine‐4,6(1H,3H,5H)‐dione in a media with pH up 7–8 to Ho≈−3 and 2‐(dinitromethylene)imidazolidine‐4,5‐dione in aqueous ammonia. ϵ‐FOX‐7 is a stable and exists in temperature range 273–378 K. ζ‐polymorph of FOX‐7 can be obtained at ϵ‐FOX‐7 heating to 378–380 K. ζ→ϵ polymorph transition is a reversible and occurs at 361.7±3.1 K. At 433–453 K ζ‐FOX‐7 transforms to γ‐polymorph. ζ→γ phase transition temperature range was determined using IR‐spectroscopy because it is invisible on DSC curves. IR‐spectra of ϵ and ζ polymorphs are significantly distinct from α‐, β‐ and γ‐FOX‐7. ϵ‐FOX‐7, in contrast to monoclinic α‐polymorph, has orthorhombic type of crystal system (space group P212121). Based on received data, new scheme of FOX‐7 polymorph transition is proposed. [ABSTRACT FROM AUTHOR]

In this paper, the compound (E)‐N‐(3,5‐dimethylphenyl)‐2‐(3‐chlorobenzylidene)thiosemicarb‐azone was synthesized and characterized by elemental analysis, Fourier transform infrared (FT‐IR), 1H nuclear magnetic resonance (NMR), 13C NMR. The crystal structure was determined by single‐crystal X‐ray diffraction tool, indicating that the compound belongs to the orthorhombic crystal system of the Fdd2 space group, where a = 14.0472(12) Å, b = 57.148(4) Å, c = 7.9633(6) Å, the chemical formula is C16H16ClN3S, Mr = 317.83, V = 6392.7(9) Å3, Z = 16, Dc = 1.321 Mg/m3, F(000) = 2656, R = 0.0339, wR = 0.0903. Analysis of crystal data shows that the molecular conformation has good planarity. Hirshfeld surface and two‐dimensional (2D) fingerprints were used to analyze the intermolecular hydrogen bonds. In addition, a more comprehensive theoretical calculation studies were carried out on synthetic compound, such as potential energy surface (PES) scan, reduced density gradient (RDG), and independent gradient model (IGM) analysis, atoms in molecules (AIM) analysis, highest occupied molecular orbital–lowest unoccupied molecular orbital (HOMO–LUMO) and UV‐visible spectra analysis. The combination of experimental and theoretical data proved that non‐covalent bonds play a vital role in maintaining the stability of molecule. Finally, molecular docking was used to research the interaction between the synthetic compound and the receptor protein (4C2L). Meanwhile, the results obtained by in vitro antifungal assay indicated that the synthetic compound possesses the most remarkable inhibitory effect for Fusarium graminearum. [ABSTRACT FROM AUTHOR]

We report the design, synthesis, and cytotoxic evaluation of a new organoruthenium(II) complex (1). Complex 1 was characterized by analytical and spectroscopic methods including single crystal X‐ray diffraction studies. Complex 1 crystallized in an orthorhombic crystal system with Pca21 space group with Ru(II) ion p‐cymene arene unit in a usual "piano‐stool" geometry. The DFT and TDFT studies were carried out to provide better insight about the spectral properties of the complex. The Hirshfeld surface analysis plots revealed significant intermolecular interactions within the crystal structure that essentially involve a network of N–H···H, O–H···O, and C–H···O linkages. DNA photocleavage activity revealed oxidative mechanistic pathway with preferential affinity toward minor groove. Cytotoxic studies of complex 1 via SRB assay revealed moderate but selective activity toward pancreatic and cervical cancer cell lines. [ABSTRACT FROM AUTHOR]

Carbonates containing CO4 groups as building blocks have recently been discovered. A new orthocarbonate, Sr2CO4 is synthesized at 92 GPa and at a temperature of 2500 K. Its crystal structure was determined by in situ synchrotron single‐crystal X‐ray diffraction, selecting a grain from a polycrystalline sample. Strontium orthocarbonate crystallizes in the orthorhombic crystal system (space group Pnma) with CO4, SrO9 and SrO11 polyhedra as the main building blocks. It is isostructural to Ca2CO4. DFT calculations reproduce the experimental findings very well and have, therefore, been used to predict the equation of state, Raman and IR spectra, and to assist in the discussion of bonding in this compound. [ABSTRACT FROM AUTHOR]

Carbonates containing CO4 groups as building blocks have recently been discovered. A new orthocarbonate, Sr2CO4 is synthesized at 92 GPa and at a temperature of 2500 K. Its crystal structure was determined by in situ synchrotron single‐crystal X‐ray diffraction, selecting a grain from a polycrystalline sample. Strontium orthocarbonate crystallizes in the orthorhombic crystal system (space group Pnma) with CO4, SrO9 and SrO11 polyhedra as the main building blocks. It is isostructural to Ca2CO4. DFT calculations reproduce the experimental findings very well and have, therefore, been used to predict the equation of state, Raman and IR spectra, and to assist in the discussion of bonding in this compound. [ABSTRACT FROM AUTHOR]

KLiSiF6 and CsLiSiF6 were synthesized via a high‐pressure/high‐temperature synthesis route. Even though, both substances crystallize in the orthorhombic crystal system with space group Pbcn (no. 60), they show different crystal structures. Main motifs of KLiSiF6 are an [SiF6]2− and an [LiF6]5− unit. In contrast, the main motifs of CsLiSiF6 are an [SiF6]2− and an [LiF5]4− entity. Within both substances, these units are interconnected and form 3‐dimensional networks. The substances were characterized via single‐crystal and powder X‐ray diffraction, as well as infrared spectroscopy and EDX measurements. Additionally, Mn4+‐doped KLiSiF6 was analyzed by means of luminescence spectroscopy. It displays line emission in the red spectral region. The maximum emission wavelength is λmax=631 nm. [ABSTRACT FROM AUTHOR]

Structural characteristics of solid and liquid crystalline phases of 7OS5 (4‐n‐pentylphenyl‐4′‐n‐heptyloxythiobenzoate), the achiral smectogenic mesogen with the shortest terminal carbon chain in the nOS5 homologous series, are studied by complementary methods. Simultaneously perfomed X‐ray diffraction and differential scanning calorimetry occur to be a powerful tool to study metastable phases. The single crystal structure of a high‐temperature phase, supercooled from the room temperature down to −183°C [orthorhombic crystal system; space group Pca21; a = 54.285 (5) Å, b = 5.5843 (3) Å, c = 14.841 (1) Å, Z = 8] is determined. Lamellar ordering of elongated molecules is stabilized by hydrogen bonds. Temperature dependence of unit‐cell parameters in two crystal phases as well as structural parameters of liquid crystalline phases (smectic layer spacing, tilt angle, average distance between the long axes of molecules and correlation lengths) are determined by X‐ray diffraction. The obtained results are compared with the data available for other compounds in the nOS5 homologous series. [ABSTRACT FROM AUTHOR]

New investigations combining single crystal‐ and synchrotron‐based powder X‐ray diffraction data revealed that Ba[Au2SnS4] crystallizes in the orthorhombic crystal system in space group C2221 instead of P21212 as reported earlier. While the principle crystal structure is not altered, there are significant differences of the interatomic distances Au‐S and Sn‐S. A salient property of this crystal structure is the partial framework composed of AuS2 dumbbells and SnS4 tetrahedra to form chains [(Au2SnS4)2–]∞ propagating in the [100] direction. Within the chains a short Au···Au separation of 2.9538(13) Å is observed, while the interchain Au···Au separation is longer at 3.383 Å. The Ba2+ cation is eightfold coordinated by S2– anions in a distorted bicapped trigonal prismatic environment BaS8. These polyhedra share all S2– anions thus generating a three‐dimensional network. This connection Scheme generates voids along [100] hosting [(Au2SnS4)2–]∞ chains. In addition, the compound has been shown to be luminescent at the blue‐green spectral range with emission maximum at approximately 21000 cm–1. [ABSTRACT FROM AUTHOR]

Two imidazolium hypodiphosphates, (C3H5N2)(H3P2O6) (I) and (C3H5N2)2(H2P2O6) (II), have been synthesized and structurally characterized. In both metal‐free organic–inorganic hybrids (I) and (II), the hypodiphosphate mono‐ and dianions, (H3P2O6)− and (H2P2O6)2−, form hydrogen‐bonded frameworks of different types, to which the organic cations are linked via N—H...O and C—H...O hydrogen bonds. The purity of the compounds was confirmed by powder X‐ray diffraction. Differential scanning calorimetry of compound (I) revealed two structural phase transitions: continuous at 311.8 K [cooling/heating; from high‐temperature phase (HTP) to room‐temperature phase (RTP)] and a discontinuous one at 287.9/289.2 K [RTP → low‐temperature phase (LTP)]. Compound (I) is characterized in a wide temperature range by single‐crystal and powder X‐ray diffraction methods. Crystal structures of high‐ and low‐temperature phases are determined, which show orthorhombic (HTP, Pnna, No. 52) → monoclinic (LTP, P21/n11, No. 14, a‐axis doubled) structural change on cooling with an intermediate incommensurately modulated phase (RTP). Dynamic properties of polycrystalline (I) were studied by means of dielectric spectroscopy. The dielectric behaviour is explained by the motion of imidazolium cations. [ABSTRACT FROM AUTHOR]

A mathematical description of crystal structure is proposed consisting of two parts: the underlying translational periodicity and the distinct atomic positions up to the symmetry operations in the unit cell, consistent with the International Tables for Crystallography. By the Cauchy–Born hypothesis, such a description can be integrated with the theory of continuum mechanics to calculate a derived crystal structure produced by solid–solid phase transformation. In addition, the expressions for the orientation relationship between the parent lattice and the derived lattice are generalized. The derived structure rationalizes the lattice parameters and the general equivalent atomic positions that assist the indexing process of X‐ray diffraction analysis for low‐symmetry martensitic materials undergoing phase transformation. The analysis is demonstrated in a CuAlMn shape memory alloy. From its austenite phase (L21 face‐centered cubic structure), it is identified that the derived martensitic structure has orthorhombic symmetry Pmmn with the derived lattice parameters ad = 4.36491, bd = 5.40865 and cd = 4.2402 Å, by which the complicated X‐ray Laue diffraction pattern can be well indexed, and the orientation relationship can be verified. [ABSTRACT FROM AUTHOR]

The crystal structure of a new superconductor UTe2 has been investigated using single‐crystal neutron diffraction for the first time at the low temperature (LT) of 2.7 K, just above the superconducting transition temperature of ∼1.6 K, in order to clarify whether the orthorhombic structure of type Immm (No. 71), reported for the room‐temperature (RT) structure persists down to the superconducting phase and can be considered as a parent symmetry for the development of spin‐triplet superconductivity. In contrast to the previously reported phase transition at about 100 K [Stöwe (1996). J. Solid State Chem. 127, 202–210], our high‐precision LT neutron diffraction data show that the body‐centred RT symmetry is indeed maintained down to 2.7 K. No sign of a structural change from RT down to 2.7 K was observed. The most significant change depending on temperature was observed for the U ion position and the U–U distance along the c direction, implying its potential importance as a magnetic interaction path. No magnetic order could be deduced from the neutron diffraction data refinement at 2.7 K, consistent with bulk magnetometry. Assuming normal thermal evolution of the lattice parameters, moderately large linear thermal expansion coefficients of about α = 2.8 (7) × 10−5 K−1 are estimated. [ABSTRACT FROM AUTHOR]

In the present study the molecular structure of compound 4‐(4,5‐diphenyl‐1H‐imidazol‐2‐yl)benzaldehyde [DPI‐BA] and its optoelectronic properties are reported. The SCXRD analysis revealed that DPI‐BA crystallizes in the Orthorhombic crystal system and Pca21 space group with Z=4. The intermolecular N‐H⋅⋅N interaction generates a one‐dimensional chain. An interesting halochromic behavior was observed for the DPI‐BA in THF:H2O (9:1) by varying the pH analysis. The fluorescence properties of neutral and acid‐base solutions were monitored by UV‐vis and 1D, 2D‐NMR studies. The HCl vapor was bubbled to the DPI‐BA in the DMSO‐d6 solution and the corresponding fluorescence wavelength changed from green (λem 501 nm) to blue (λem 459 nm). In the case of a basic pH solution was made by adding NaOH flakes to the DPI‐BA DMSO‐d6 solution and then the fluorescence wavelength changed from green to orange (λem 595 nm). The λmax of PL emission could be correlated to intermolecular charge transfer (ICT). The optical absorption and cyclic voltammetry measurement were performed to determine the bandgap. Besides, the quantitative analysis of intermolecular interactions through PIXEL, QTAIM, NBO, GIAO‐DFT methods and DFT studies was correlated to the experiments. [ABSTRACT FROM AUTHOR]

The preparation and structural characterization of an original Th peroxo sulfate dihydrate, crystallizing at room temperature in the form of stable 1D polymeric microfibres is described. A combination of laboratory and synchrotron techniques allowed solution of the structure of the Th(O2)(SO4)(H2O)2 compound, which crystallizes in a new structure type in the space group Pna21 of the orthorhombic crystal system. Particularly, the peroxide ligand coordinates to the Th cations in an unusual μ3‐η2:η2:η2 bridging mode, forming an infinite 1D chain decorated with sulfato ligands exhibiting simultaneously monodentate and bidentate coordination modes. [ABSTRACT FROM AUTHOR]

A big challenge for nonlinear optical (NLO) materials is the application in high power lasers, which needs the simultaneous occurrence of large second harmonic generation (SHG) and high laser induced damage threshold (LIDT). Herein we report the preparation of a new Ga2Se3 phase, which shows the SHG intensities of around 2.3 times and the LIDT of around 16.7 times those of AgGaS2 (AGS), respectively. In addition, its IR transparent window ca. 0.59–25 μm is also significantly wider than that of AGS (ca. 0.48–≈11.4 μm). The occurrence of the strong SHG responses and good phase‐matching indicate that the structure of the new Ga2Se3 phase can only be non‐centrosymmetric and have a lower symmetry than the cubic γ‐phase. The observed excellent SHG and phase‐matching properties are consistent with our diffraction experiments and can be well explained by using the orthorhombic models obtained through our high throughput simulations. [ABSTRACT FROM AUTHOR]

FeNb11O29, with the possibility to exchange up to 23 electrons per formula unit and a theoretical capacity value of 400 mAh/g, is nowadays a very promising anode material for Li‐ion batteries. However, the improvement of its electrochemical performances is still an open challenge, and the doping is a well‐recognized method to obtain this goal. In this paper, orthorhombic Fe0.8Mn0.2Nb11O29 and Fe0.8V0.2Nb11O29 samples were prepared by solid state synthesis. The redox processes, as determined by cyclic voltammetry, involve only Fe and Nb ions as in the undoped compound. FeNb11O29 is a well‐known mixed oxide with pseudocapacitive behavior, which is increased with the Mn doping. The doped samples show better performances during long term cycling at 2 C, with capacities of 240 and 220 mAh/g and capacity retention of 100.9 and 98.7% for Mn and V doped respectively. [ABSTRACT FROM AUTHOR]

Lead‐free 0.99(0.96K0.46Na0.54Nb1‐xTaxO3‐0.04Bi0.5(Na0.82K0.18)0.5ZrO3)‐0.01CaZrO3 (0.99(0.96KNNTax‐0.04BNZ)‐0.01CZ) ceramics were prepared by a solid‐state sintering method. Ta2O5 doped in the 0.99(0.96KNNTax‐0.04BNZ)‐0.01CZ ceramics results in a phase structure transition from the orthorhombic (O)/tetragonal (T) phase to the rhombohedral (R)/T phase. The Ta2O5 dopant induces a decrease in the average grain size from ~1.70 to ~0.69 μm. At x = 0.02 and 0.04, the ceramics have a high reverse piezoelectric coefficient (~500 pm/V under 25 kV/cm). The ceramics with x = 0.04 show an optimal level of unipolar strain, reaching 0.17% under 35 kV/cm at room temperature, and their field‐induced strain varies <10% in the temperature range from 25 to 135°C. The presence of the O phase in the polymorphic phase boundary (PPB) improves the temperature stability the reverse piezoelectric coefficient (d33∗). Obtaining KNN‐based ceramics with good piezoelectric properties and weak temperature sensitivity by designing a R/O/T phase boundary and controlling the average grain size to the submicrometer level is highly feasible. [ABSTRACT FROM AUTHOR]

Determination of the crystal structures of low‐temperature tridymite and cristobalite using single‐crystal XRD has been challenging because they generally occur as metastable fine‐grained crystals in the geological environment. Therefore, using powder diffraction and scattering techniques is critical to study the low‐temperature crystals. Synchrotron powder X‐ray diffraction (XRD), pair distribution function (PDF) and transmission electron microscopy were used to investigate the structure of orthorhombic tridymite with C2221 symmetry and tetragonal cristobalite with P41212 symmetry, including their anisotropic atomic displacement parameters (ADPs). Rietveld refinement was used to determine the unit‐cell parameters, fractional coordinates and isotropic atomic displacement parameters (Uiso) of the tridymite and cristobalite. The PDF method was used to determine ADPs for each atom. The results suggest that the crystal structure with high quality ADP values can be obtained using the combined methods of XRD and PDF analyses. The method can be used for characterizing crystals that are not suitable for single‐crystal XRD. Anisotropic atomic displacement parameters of orthorhombic tridymite and tetragonal cristobalite can be determined accurately using the combined methods of powder XRD and pair distribution function analysis. [ABSTRACT FROM AUTHOR]

Dielectric ceramics are one of the most important electrical insulators because of their excellent electrical stability and nonconducting properties. In this work, new complex perovskite solid solutions, (1−x)Pb(Mg1/2W1/2)O3–xPbHfO3 [(1−x) PMW–xPHf] (0.00 ≤ x ≤ 0.04), were successfully synthesized in the form of ceramics by the solid‐state reaction method and sintering process. The X‐ray diffraction results indicate that a single perovskite phase with antiferroelectric (AFE) orthorhombic Pmcn symmetry is formed for x < 0.04 which corresponds to the PMW‐type solid solution (SS‐PMW). For the composition x = 0.04, however, a small amount (about 1%) of ferroelectric orthorhombic C2mm phase that arises from the PHf‐type solid solution (SS‐PHf) was found to coexist with the Pmcn phase (99%). The dielectric measurements show that the AFE‐paraelectric phase transition temperature TC of the (1−x)PMW–xPHf ceramics increases from 38.2°C (x = 0) to 40.1°C (x = 0.03) with the increasing PHf content, indicating a slightly enhanced AFE ordering degree. The studied materials show a relatively low dielectric constant (~102), a low dielectric loss (~10−2), a high breakdown field strength (~140 kV/cm), and a linear electric field dependence of polarization at room temperature, which make them a new candidate for potential applications as ceramic insulators. Dielectric ceramics are one of the most important electrical insulators because of their excellent electrical stability and non‐conducting properties. The studied materials show an stable antiferroelectricity, low dielectric constant and loss, high dielectric breakdown strength, and low polarization at room temperature, which make them a new candidate for potential applications as ceramic insulators. [ABSTRACT FROM AUTHOR]

The orthorhombic structure of Lanthanum orthoferrite (LaFeO3) was synthesised by a facile hydrothermal method. The hydrothermal reaction time and potassium hydroxide (KOH) concentration play an important role in the formation of LaFeO3 microcubes. The obtained samples were characterised by several analysis techniques such as X-ray diffraction, scanning electron microscope, ultraviolet--visible (UV--vis) absorption spectroscopy, and photoluminescence (PL) emission spectroscopy for identifying their structural and optical characteristics. On the basis of experimental results, it can be concluded that the obtained samples have been structurally characterised which confirms the orthorhombic LaFeO3 structure. Meanwhile, the results depict that highly pure and monodisperse LaFeO3 microcubes are successfully obtained when synthesised at the alkaline source of 4.5 g KOH and maintained at 240°C for 16 h, which have an average diameter of ~7 μm. The subsequent plausible formation mechanism of the LaFeO3 microstructure has been explained on the basis of the Ostwald ripening process. Subsequently, the optical properties of the prepared sample were investigated and optimised, and the UV--vis data showed that the microstructure was a visible light absorbing semiconductor with a narrow bandgap. In addition, PL spectra indicate that the LaFeO3 microcubes synthesised by this technique can be considered as a photocatalytic material. [ABSTRACT FROM AUTHOR]

Dielectric ceramics are one of the most important electrical insulators because of their excellent electrical stability and nonconducting properties. In this work, new complex perovskite solid solutions, (1−x)Pb(Mg1/2W1/2)O3–xPbHfO3 [(1−x) PMW–xPHf] (0.00 ≤ x ≤ 0.04), were successfully synthesized in the form of ceramics by the solid‐state reaction method and sintering process. The X‐ray diffraction results indicate that a single perovskite phase with antiferroelectric (AFE) orthorhombic Pmcn symmetry is formed for x < 0.04 which corresponds to the PMW‐type solid solution (SS‐PMW). For the composition x = 0.04, however, a small amount (about 1%) of ferroelectric orthorhombic C2mm phase that arises from the PHf‐type solid solution (SS‐PHf) was found to coexist with the Pmcn phase (99%). The dielectric measurements show that the AFE‐paraelectric phase transition temperature TC of the (1−x)PMW–xPHf ceramics increases from 38.2°C (x = 0) to 40.1°C (x = 0.03) with the increasing PHf content, indicating a slightly enhanced AFE ordering degree. The studied materials show a relatively low dielectric constant (~102), a low dielectric loss (~10−2), a high breakdown field strength (~140 kV/cm), and a linear electric field dependence of polarization at room temperature, which make them a new candidate for potential applications as ceramic insulators. Dielectric ceramics are one of the most important electrical insulators because of their excellent electrical stability and non‐conducting properties. The studied materials show an stable antiferroelectricity, low dielectric constant and loss, high dielectric breakdown strength, and low polarization at room temperature, which make them a new candidate for potential applications as ceramic insulators. [ABSTRACT FROM AUTHOR]

Powder samples of the compounds (A3N)As (A = Mg, Ca, Sr, Ba) were prepared by reacting the respective alkaline earth metal nitrides and arsenic in nickel ampoules. (Mg3N)As crystallizes in a cubic unit cell (space group Pm3m, no. 221) with inverse perovskite structure. The analogous compounds of calcium, strontium, and barium crystallize in an orthorhombic unit cell (space group Pnma, no. 62) as distorted inverse perovskites in the GdFeO3 structure type. The degree of distortion was quantified based on a newly developed vectorial comparison of the atomic sites of coordination polyhedra with the ideal positions (PolyDis). Based on this analysis, the distortion increases with the size of the alkaline earth metal cation. [ABSTRACT FROM AUTHOR]

Two low‐firing BiMVO5 (M = Ca, Mg) ceramics were prepared in the sintering temperature range of 760‐850°C. Their differences in phase formation, sintering behavior, and dielectric performances were investigated. BiCaVO5 formed a single phase with an orthorhombic structure, while BiMgVO5 crystallized in a monoclinic structure that needs longer dwelling time to obtain single phase. The optimized microwave dielectric properties were obtained with εr = 15.70, Q × f = 55 000 GHz (at 10.6 GHz), and τf = −71 ppm/°C for BiCaVO5, εr = 18.55, Q × f = 86 860 GHz (at 9.63 GHz), and τf = −65 ppm/°C for BiMgVO5. In addition, the large negative τf values of BiMVO5 (M = Ca, Mg) ceramics were successfully adjusted by forming composite ceramics with CaTiO3 and near‐zero τf values of +2 ppm/°C and −3 ppm/°C were obtained in 0.92BiCaVO5‐0.08CaTiO3 and 0.94BiMgVO5‐0.06CaTiO3, respectively. Both ceramics exhibited good chemical compatibility with Ag electrode. The results demonstrate BiMVO5 (M = Ca, Mg) ceramics to be attractive candidates in LTCC technology. [ABSTRACT FROM AUTHOR]

A simple, economical successive ionic layer adsorption and reaction (SILAR) method has been used for synthesizing 1, 2 and 3 at.% copper‐doped strontium hydroxide over a stainless‐steel (SS) substrate. X‐ray diffraction reveals the orthorhombic crystal structure of polycrystalline Cu‐doped Sr(OH)2. FTIR and Raman analyses explore the chemical bond analysis of the active material. The morphology of the Cu‐doped Sr(OH)2 was analyzed by using SEM. This shows novel hierarchical‐branched tuberose with flakes. The energy‐dispersive X‐ray spectroscopy (EDAX) also confirms the doping of Cu into Sr(OH)2. The electrochemical properties have been investigated by using cyclic voltammetry (CV) and galvanostatic charge−discharge measurements. It has been perceived that doping clearly affects the supercapacitive behavior. The specific capacity of the 3 at.% Cu‐doped Sr(OH)2 film electrode exhibits a maximum specific capacity of 817 C g−1 at 0.4 mA cm−1 in 1 M Na2SO4 electrolyte, but has a low cycle stability. The 2 at.% Cu‐doped sample shows high cycle stability by retrieving 71 % of its capacity after 5000 cycles. The relationship between the doping concentration and supercapacitive behavior has also been discussed. The good capacitive behavior and cycle stability of the Cu‐doped Sr(OH)2 gives the new perspective for the flexible electrode material, which can be used in the near future as an energy storage material. ′Caps off: Tuberose with a flake‐like structure and Cu‐doped Sr(OH)2 is fabricated by using a low‐cost wet chemical SILAR technique. The unique morphology and superior specific capacity is demonstrated. The influence of Cu on the morphology as well as the supercapacitive behavior is investigated. [ABSTRACT FROM AUTHOR]

The crystal structure of divainillin (systematic name: 6,6′‐dihydroxy‐5,5′‐dimethoxy‐[1,1′‐biphenyl]‐3,3′‐dicarbaldehyde), C16H14O6, was determined from laboratory powder X‐ray diffraction data using the software EXPO2013 (direct methods) and WinPSSP (direct‐space approach). Divanillin molecules crystallize in the orthorhombic space group Pba2 (No. 32), with two molecules per unit cell (Z′ =). Each divanillin molecule, with twofold symmetry, is linked through strong alcohol–aldehyde hydrogen bonds to four equivalent molecules, defining a three‐dimensional hydrogen‐bonding network, with rings made up of six divanillin units (a diamond‐like arrangement). Each molecule is also connected through π–π interactions to a translation‐equivalent molecule along c. Four consecutive molecules stacked along [001] belong to four different three‐dimensional hydrogen‐bonding networks defining a quadruple array of interpenetrating networks. This complex hydrogen‐bonding array is proposed as an explanation for the aging process experienced by divanillin powders. The crystal structure of divanillin was solved and refined from laboratory powder X‐ray diffraction data. The crystal structure is composed of an intricate diamond‐type arrangement of four interpenetrating hydrogen‐bonded networks that explains the different solubilities of the freshly synthesized material and the product aged for 15 min in the mother liquor. [ABSTRACT FROM AUTHOR]

While the synthesis of chloro formamidinium chloride has been known for over one century, no solid‐state structure of a chlorine‐substituted formamidinium compound has been reported up to now. Herein, we describe syntheses, solid‐state structures, and vibrational properties of four chloro formamidinium compounds, namely [ClC(NH2)2]Cl (1), [ClC(NH2)2](AuCl4) (2), [ClC(NH2)2]2(PdCl4) (3), and [ClC(NH2)2]2(PtCl6) (4), as determined by single‐crystal X‐ray diffraction (SCXRD). 1 and 3 crystallize in the monoclinic space group P21/c, 2 in the orthorhombic space group Pbcn, whereas 4 adopts the triclinic space group P1. By using a combination of high‐resolution time‐of‐flight neutron powder diffraction, state‐of‐the‐art DFT calculations as well as IR spectroscopy, the prior SCXRD result was fully confirmed and augmented by determining the hydrogen‐bonded molecular networks. First‐principles electronic‐structure calculations corroborate the ionic nature of these salts by showing very flat, molecular‐like bands next to the Fermi level, in addition to indirect bandgaps. This study underlines the upmost importance of complementing diffraction data by ab initio calculations, as theory‐derived anisotropic displacement parameters served as fixed numerical entries. [ABSTRACT FROM AUTHOR]

The ternary rare‐earth iridium gallides RE6Ir5Ga7 (RE = Sc, Y, Nd, Sm, Gd – Tm, and Lu) were synthesized from the elements by arc‐melting or by induction melting in sealed niobium ampoules. The samples were structurally characterized by X‐ray powder diffraction. The structure of Sc6Ir5Ga7 was refined from single‐crystal X‐ray diffractometer data: Yb6Ir5Ga7 (Nb6.4Ir4Al7.6) type, P63/mcm, a = 912.84(7), c = 828.07(6) pm, wR2 = 0.0362, 504 F2 values and 22 variables. The RE6Ir5Ga7 gallides crystallize with a fully ordered superstructure of the hexagonal Laves phase MgZn2. The zinc substructure consists of ordered and condensed Ir3Ga and IrGa3 tetrahedra. Further phase analytical studies in the RE‐Ir‐Ga systems led to the new equiatomic gallides SmIrGa and LuIrGa with the orthorhombic, TiNiSi type structure, space group Pnma. The samarium compound shows a pronounced solid solution SmIr1–xGa1+x, which was confirmed by single crystal structure refinements for SmIr0.95Ga1.05, SmIr0.69Ga1.31 and SmIr0.55Ga1.45. The RE6Ir5Ga7 and REIrGa gallides show pronounced covalent Ir–Ga bonding. [ABSTRACT FROM AUTHOR]

The close relationship of C60 and deltahedral tetrel element cluster anions has been pointed out before. We report herein on UV/Vis spectra of the Zintl anions and compounds [Ge9]2–, [(CH2=CH)2Ge9]2–, [{(Me3Si)3Si}3Ge9]–, {(Me3Si)3Si}3Ge9CH2CH3, {(Me3Si)3Si}3Ge9(CH2)2CH3, {(Me3Si)3Si}3Ge9(CH2)3CH=CH2, and [{(Me3Si)3Si}3Ge9CH2CH3]Pt(PPh3). The spectra are compared to those of the C60 fullerene, which were recorded under the same conditions. The UV/Vis spectrum of pristine [Ge9]2– resembles that of C60 and at higher concentration hint at the known trimeric [(Ge9)3]6–. The influence of ligand substitution at the Ge9 cluster‐core is highlighted. For this, the synthesis of the specifically functionalized deltahedral Ge9 clusters {(Me3Si)3Si}3Ge9(CH2)2CH3, {(Me3Si)3Si}3Ge9(CH2)2CH=CH2, and {(Me3Si)3Si}3Ge9(CH2)3C6H5 are reported for the first time and is achieved by the reaction of K[{(Me3Si)3Si}3Ge9] with the respective alkyl halides in acetonitrile. The newly synthesized products were characterized by NMR spectroscopy. [ABSTRACT FROM AUTHOR]

The ternary rare‐earth iridium gallides RE6Ir5Ga7 (RE = Sc, Y, Nd, Sm, Gd – Tm, and Lu) were synthesized from the elements by arc‐melting or by induction melting in sealed niobium ampoules. The samples were structurally characterized by X‐ray powder diffraction. The structure of Sc6Ir5Ga7 was refined from single‐crystal X‐ray diffractometer data: Yb6Ir5Ga7 (Nb6.4Ir4Al7.6) type, P63/mcm, a = 912.84(7), c = 828.07(6) pm, wR2 = 0.0362, 504 F2 values and 22 variables. The RE6Ir5Ga7 gallides crystallize with a fully ordered superstructure of the hexagonal Laves phase MgZn2. The zinc substructure consists of ordered and condensed Ir3Ga and IrGa3 tetrahedra. Further phase analytical studies in the RE‐Ir‐Ga systems led to the new equiatomic gallides SmIrGa and LuIrGa with the orthorhombic, TiNiSi type structure, space group Pnma. The samarium compound shows a pronounced solid solution SmIr1–xGa1+x, which was confirmed by single crystal structure refinements for SmIr0.95Ga1.05, SmIr0.69Ga1.31 and SmIr0.55Ga1.45. The RE6Ir5Ga7 and REIrGa gallides show pronounced covalent Ir–Ga bonding. [ABSTRACT FROM AUTHOR]

The realization of n‐type Ge chalcogenides is elusive owing to intrinsic Ge vacancies that make them p‐type semiconductors. GeSe crystallizes into a layered orthorhombic structure similar to SnSe at ambient conditions. The high‐symmetry cubic phase of GeSe is predicted to be stabilized by applying 7 GPa external pressure or by enhancing the entropy by increasing to temperature to 920 K. Stabilization of the n‐type cubic phase of GeSe at ambient conditions was achieved by alloying with AgBiSe2 (30–50 mol %), enhancing the entropy through solid solution mixing. The interplay of positive and negative chemical pressure anomalously changes the band gap of GeSe with increasing the AgBiSe2 concentration. The band gap of n‐type cubic (GeSe)1−x(AgBiSe2)x (0.30≤x≤0.50) has a value in the 0.3–0.4 eV range, which is significantly lower than orthorhombic GeSe (1.1 eV). Cubic (GeSe)1−x(AgBiSe2)x exhibits an ultralow lattice thermal conductivity (κL≈0.43 W m−1 K−1) in the 300–723 K range. The low κL is attributed to significant phonon scattering by entropy‐driven enhanced solid‐solution point defects. n‐Type cubic GeSe has been stabilized at ambient conditions by entropy‐driven formation of a solid solution with AgBiSe2. It demonstrated promising thermoelectric properties with ultralow thermal conductivity. Upon increasing the AgBiSe2 concentration in GeSe, the band gap of the system changes anomalously. [ABSTRACT FROM AUTHOR]

The single-side Al-centred tris-functionalized hybrid organic-inorganic Anderson polyoxomolybdates (C16H36N)3[Al(OH)3Mo6O18(OCH2)3CNH(C10H8 O)]·C9H7- N·4CH3OH·5H2O (AlMo6-NH-Cin; Cin is cinnamic acid, C10H9O2) and (C16H36N)3[Al(OH)3Mo6O18 (OCH2)3CNH(C19H15ClNO3)]·9H2O (AlMo6-NHIndo; Indo is indometacin, C19H16ClNO4) have been prepared in a mild threestep synthesis and structurally characterized by single-crystal X-ray diffraction, 1H NMRand IR spectroscopies and elemental analysis. Both AlMo6-NH-Cin and AlMo6-NH-Indo crystallize in the orthorhombic space group Pbca. The antibacterial activities of AlMo6-NH-Cin and AlMo6-NH-Indo against the Gram-negative human mucosal pathogen Moraxella catarrhalis were investigated by determination of the minimum inhibitory concentration, which is 32 mg ml-1 for AlMo6-NH-Cin and 256 μg ml-1 for AlMo6-NH-Indo. [ABSTRACT FROM AUTHOR]

This study shows that the anomeric effect (negative hyperconjugation) that arises in sulfamide, as a result of the relatively short S−N bonds, can be tuned by the utilization of superacidic media. Sulfamide was reacted in binary superacidic systems XF/MF5 (M=As, Sb; X=H, D) and HF/BF3. The colorless salts formed, [X2NSO2NX3]+[MF6]− and [H2NSO2NH3]+[BF4]− were characterized by low‐temperature vibrational spectroscopy. In the case of [H2NSO2NH3]+[BF4]−, a single crystal X‐ray diffraction study was performed. The salt crystallizes in the monoclinic space group P21/c with four formula units per unit cell. An exclusive N,N′‐diprotonation was observed in the superacidic system HF/SbF5 when using several equivalents of the Lewis acid. Low‐temperature vibrational spectra as well as a single‐crystal X‐ray structure of [H3NSO2NH3]2+2 [SbF6]−⋅2 HF are reported. The salt crystallizes in the orthorhombic space group Pna21 with four formula units per unit cell. Upon mono‐ or diprotonation of sulfamide, remarkable structural changes of the sulfur–nitrogen bond lengths were observed. Herein, these changes are discussed together with quantum chemical calculations. Structural effects: Sulfamide undergoes remarkable structural changes upon protonation. Dependent on the amount of the Lewis acids AsF5 or SbF5 with respect to sulfamide, salts containing [H2NSO2NH3]+ (I) and [H3NSO2NH3]2+ (II) are isolable. The structural changes are discussed in the context of the anomeric effect. [ABSTRACT FROM AUTHOR]

Abstract: Although nitride phosphors have been wildly researched, CaSiN2 is seldom reported. In this paper, two different phases CaSiN2, orthorhombic and cubic phase prepared by plasma‐activated sintering were reported. Without active ions doped, the samples were pure orthorhombic phase. However, when Eu ions were doped into CaSiN2, the samples were consisted of both orthorhombic phase and cubic phase, and the ratio of two phases would change with the sintering temperature changed. Meanwhile, the photoluminescence (PL) intensity of samples would change adversely with the content of cubic phase. The differences between the structures of two phases and the existence form of Eu ions in different phases were reported. It can be inferred that the Eu2+ ions prefer to enter into cubic phase when two phases coexist, and the Eu2+ will be translated to Eu3+ easily due to the loose coordination environment in cubic phase, which will result in weaker PL intensity and worse thermal stability. [ABSTRACT FROM AUTHOR]

High‐pressure silica polymorphs may contribute to lithologies in Earth's lower mantle. Stishovite, the tetragonal rutile‐type polymorph of SiO2, distorts to an orthorhombic CaCl2‐type structure at pressures and temperatures of the lower mantle. We compressed sintered polycrystalline stishovite and determined the unit cell parameters as a function of pressure using synchrotron X‐ray diffraction. The compression behavior of sintered polycrystalline stishovite deviates systematically from previous results on stishovite powder and single crystals. Following an initial stiffening, the bulk modulus of sintered polycrystalline stishovite drops at the ferroelastic phase transition. We analyzed the observed spontaneous strains using Landau theory to predict the complete elastic behavior of sintered polycrystalline silica across the phase transition. The reduction in bulk modulus at the phase transition as derived here from the compression curve of sintered polycrystalline silica may have implications for the seismic detection of silica‐rich materials in Earth's lower mantle. Plain Language Summary: When rocks from Earth's surface sink into Earth's deep interior, the component minerals change in response to the high pressures and high temperatures. Among others, a mineral called stishovite forms. Stishovite has the same chemical formula as quartz but a higher density. At depths beneath 1,500 km, the stishovite crystals distort spontaneously to adapt to higher pressures. Because of this inherent tendency of the crystals to distort, they become elastically softer close to the pressure at which they distort spontaneously. We measured the compressibility of stishovite at high pressures and found that stishovite is less compressible when many stishovite crystals are firmly connected to each other. When the crystals distort, however, the polycrystalline material suddenly becomes more compressible again. Because seismic waves travel slower in elastically soft and compressible materials, we conclude that seismic waves might be slowed down by stishovite close to those pressures or depths where the stishovite crystals distort. The change of the elastic properties of stishovite might even result in seismic waves bouncing off rocks that contain stishovite. Such seismic waves can be detected on Earth's surface and may be used to infer the presence of stishovite in Earth's lower mantle. Key Points: We compressed sintered polycrystalline stishovite across the ferroelastic tetragonal‐orthorhombic phase transitionThe compression behavior of sintered polycrystalline stishovite deviates systematically from powderThe bulk modulus of sintered polycrystalline stishovite drops at the ferroelastic phase transition [ABSTRACT FROM AUTHOR]

Abstract: CuO‐added 0.96(Na0.5K0.5)(Nb1‐xSbx)O3‐0.04SrTiO3 ceramics sintered at the low temperature of 960°C for 10 hours showed dense microstructures and high relative densities. The specimens with 0.0 ≤  x ≤ 0.04 had orthorhombic‐tetragonal polymorphic phase boundary (PPB) structure. Tetragonal‐pseudocubic PPB structure was observed in specimens with 0.05 ≤  x ≤ 0.07, while the specimen with x = 0.08 has a pseudocubic structure. The structural variation in the specimens is explained by the decreases in the orthorhombic‐tetragonal transition temperature and Curie temperature with the addition of Sb5+ ions. The specimens with 0.05 ≤  x ≤ 0.07, which have tetragonal‐pseudocubic PPB structure, had large electric field‐induced strains of 0.14%‐0.016%. Moreover, these specimens also showed increased d33 values between 280 pC/N and 358 pC/N. In particular, the specimen with x = 0.055 showed particularly enhanced piezoelectric properties: d33 of 358 pC/N, kp of 0.45, and the electric field‐induced strain of 0.16% at 4.5 kV/mm. [ABSTRACT FROM AUTHOR]

Abstract: Shockwave data on mineral‐forming compounds such as Mg2SiO4 are essential for understanding the interiors of Earth and other planets, but correct interpretation of these data depends on knowing the phase assemblage being probed at high pressure. Hence, direct observations of the phase or phases making up the measured states along the forsterite Hugoniot are essential to assess whether kinetic factors inhibit the achievement of the expected equilibrium, phase‐separated assemblage. Previous shock recovery experiments on forsterite, which has orthorhombic space group Pbnm, show discrepant results as to whether forsterite undergoes segregation into its equilibrium phase assemblage of compositionally distinct structures upon shock compression. Here we present the results of plate impact experiments on polycrystalline forsterite conducted at the Dynamic Compression Sector of the Advanced Photon Source. In situ X‐ray diffraction measurements were used to probe the crystal structure(s) in the shock state and to investigate potential decomposition into periclase and bridgmanite. In contrast to previous interpretations of the forsterite shock Hugoniot, we find that forsterite does not decompose but instead reaches the forsterite III structure, which is a metastable structure of Mg2SiO4 with orthorhombic space group Cmc21. [ABSTRACT FROM AUTHOR]

Metastable compounds accessible through kinetic stabilization or under conditions of constrained equilibrium represent a richly varied landscape of structures, properties, and function that are oftentimes entirely inaccessible in thermodynamic minima. The multiple redox states of vanadium and the ability to modulate the connectivity of vanadium and oxygen atoms yields a rich diversity of structures for binary vanadium oxides. Here, it is demonstrated that an orthorhombic quasi‐1D polymorph of VO2, characterized by extended tunnels with a rectangular cross‐section, can be stabilized through the substitutional doping of iridium on the vanadium sublattice. The obtained structure is considerably distorted from a previously reported paramontroseite mineral phase. The metastable phase is obtained in nanoplatelet form and is stable with respect to the energetically proximate monoclinic/rutile thermodynamic minima up to a temperature of 350 °C. The open framework structure and the accessibility of multiple redox states at the vanadium center suggests that the polymorph could potentially serve as an intercalation host. Beyond the solubility limit of iridium on the vanadium sublattice (1.28–3.15 at.% depending on the precursor concentration), metallic Ir nanocrystals are found to be homogeneously dispersed on the surfaces of the nanoplatelets indicating a strong interaction between the metal nanocrystals and oxide lattice. [ABSTRACT FROM AUTHOR]

Dimethylsulfone reacts in the binary superacidic systems XF/MF5 (X = H, D; M = As, Sb) under the formation of the corresponding salts of the type [(CH3)2SO(OX)]+[MF6]–. The salts are characterized by low temperature vibrational spectroscopy. In case of [(CH3)2SO(OH)]+[SbF6]– a single‐crystal X‐ray structure analysis is reported. The salt crystallizes in the orthorhombic space group Pbca with eight formula units per unit cell [a = 10.3281(3) Å, b = 12.2111(4) Å, c = 13.9593(4) Å]. The experimental results are discussed together with quantum chemical calculations on the PBE1PBE/6‐311G++(3pd,3df) level of theory. [ABSTRACT FROM AUTHOR]

Abstract: The hybrid organic–inorganic perovskites are known to exhibit a complex crystalline structure, which allows for the structural phase transitions among the orthorhombic, tetragonal, and cubic phases that occur at different temperatures. This behavior of the organic–inorganic perovskites can significantly alter their optoelectronic properties. Here, using photoluminescence spectroscopy, it is shown that the structural orthorhombic‐to‐tetragonal phase transition temperature in MAPbI3 perovskite crystal can be increased from 135 to 160 K upon coating with ZnO nanoshell. The phenomenon is attributed to the interfacial‐field‐induced atomic rearrangement in the near‐surface area. The findings shed light on the great importance of the interfacial electric field effect on the structural and optical properties of the organic–inorganic perovskites, which hold great promise for their potential applications in the structural‐phase‐controlled optoelectronic and photovoltaic devices. [ABSTRACT FROM AUTHOR]

The defect structures and electronic properties of orthorhombic elongated (OE) and tetragonal compressed (TC) Rh2+ centers in LiD are theoretically studied using Density Functional Theory (DFT) with the periodic CP2K program. The calculations demonstrate obvious differences in defect structure between the two centers. OE center with one next nearest neighbor (nnn) cation vacancy (VLi) in [100] axis shows the Jahn‐Teller elongation of about 0.076 Å along [001] axis, whereas TC center with one nnn VLi in [001] axis exhibits a compression of about 0.049 Å along this direction. The ligand between the central Rh2+ and the VLi is found to move away from the VLi by about 0.038 or 0.035 Å for O­­E or TC center. The larger magnitude of the overlap population (≈ −0.5907 or −0.5494 e) of the RhD bonds in OE or TC center than that (≈0.2373 e) of the host LiD bonds in pure LiD indicates much stronger covalency of the former. The simulated UV–Vis and electron paramagnetic resonance (EPR) spectra with the embedded cluster model in ORCA code are consistent with the experimental data. The present results are discussed and compared with those of the previous perturbation calculations. [ABSTRACT FROM AUTHOR]

Abstract: The famous heat‐resistant explosive‐2,2’,2’’,4,4’,4’’,6,6’,6’’‐nonanitro‐1,1’:3’,1’’‐terphenyl (NONA) was synthesized by the Ullmann reaction, and its separation and purification was achieved by the solvent‐antisolvent method and the anisole reflux method, which are more simple and easy to operate than conventional methods. The molecular structure of NONA was characterized by X‐ray single crystal diffraction, FT‐IR, 1H NMR, mass spectrometry and elemental analysis. The thermal behavior of NONA was studied by thermogravimetric‐differential scanning calorimetry (TG‐DSC), Moreover, the heats of formation, detonation properties, and bond dissociation of NONA were calculated. The results show that the NONA crystals belong to the orthorhombic system and the Pbca (61) space group where a=16.8223 (11) Å, b=11.9573 Å, c=23.0972 (14) Å, a/b=1.4069, b/c=0.5177, c/a=1.3730, V=4645.99(50) Å3, ρ=1.81644 g/cm3, Z=8, and F(000)=2560. The decomposition temperature is 364.8 °C, the calculated heats of formation is −148.2 kJ/mol, the detonation velocity and detonation pressure are 7720.66 m/s and 26.58 GPa, respectively, and the initiation bond is C(3)‐NO2 with a dissociation energy of 249.3 kJ/mol. [ABSTRACT FROM AUTHOR]

The hydrothermal synthesis and structural characterization of new trivalent rare‐earth germanates, Na4[(Y1–aLna)2Ge4O13] (Ln = Eu, Tb, or Yb and Er; a = 0.05, 0.1) and Na4[(Yb0.9Er0.1)2Ge4O13] are reported. The structure of these solids was solved by single‐crystal X‐ray diffraction (150 K). The materials crystallize in the orthorhombic non‐centrosymmetric Pna21 space group, and exhibit a framework comprising unprecedented anionic tetrameric [Ge4O13]10– units, tetrameric units of {GeO4} tetrahedra, and isolated dimeric units encompassing two distinct distorted {REO6} octahedra. These rare‐earth germanates feature interesting photoluminescence properties in the visible and near‐infrared spectral regions. Eu3+ photoluminescence confirms the presence of two distinct rare‐earth sites. Energy transfer between the latter sites is shown for the Yb3+/Er3+ pair, both displaying significant near‐infrared emission. Isomorphous Na4[(Yb0.9Er0.1)2Ge4O13] features up‐conversion emission, an unusual property among rare‐earth crystalline germanates. [ABSTRACT FROM AUTHOR]

Chlorosulfonamide reacts in the superacidic solutions HF/GeF4 and HF/AsF5 under the formation of ([ClSO2NH3]+)2[GeF6]2– and [ClSO2NH3]+[AsF6]–, respectively. The chlorosulfonammonium salts were characterized by X‐ray single crystal structure analysis as well as vibrational spectroscopy and discussed together with quantum chemical calculations. ([ClSO2NH3]+)2[GeF6]2– crystallizes in the triclinic space group P 1 with one formula unit in the unit cell. [ClSO2NH3]+[AsF6]– crystallizes in the monoclinic space group P21/n with four formula units in the unit cell. Dependent on the counterion, [AsF6]– or [GeF6]2–, considerable structural differences of the [ClSO2NH3]+ cation are observed. Furthermore, the hitherto unknown X‐ray single crystal structure of chlorosulfonamide is determined in the course of this study. Chlorosulfonamide crystallizes in the orthorhombic space group Pmc2 with four formula units per unit cell. [ABSTRACT FROM AUTHOR]

The origin of the complex reflection splitting in potassium sodium niobate doped with lithium and manganese was investigated using temperature‐dependent high‐resolution X‐ray and neutron diffraction as well as electron probe microanalysis and scanning electron microscopy. Two structural models were developed from the diffraction data. A single‐phase monoclinic Pm model is known from the literature and is able to reproduce the diffraction patterns perfectly. However, a model with phase coexistence of two classical orthorhombic Amm2 phases can also reproduce the diffraction data with equal accuracy. Scanning electron microscopy in combination with electron probe microanalysis revealed segregation of the A‐site substituents potassium and sodium. This favours the model with phase coexistence and confirms the need for comprehensive analyses with complementary methods to cover a broad range of length scales as well as to assess both average and local structure. [ABSTRACT FROM AUTHOR]

Abstract: Orthorhombic Nb2O5 (T‐Nb2O5) has recently attracted great attention for its application as an anode for sodium ion batteries (NIBs) owing to its patulous framework and larger interplanar lattice spacing. Sulfur‐doped T‐Nb2O5 hollow nanospheres (diameter:180 nm) uniformly encapsulate into sulfur‐doped graphene networks (denoted: S‐Nb2O5 HNS@S‐rGO) using hard template method. The 3D ordered porous structure not only provides good electronic transportation path but also offers outstanding ionic conductive channels, leading to an improved sodium storage performance. In addition, the introduction of sulfur to graphene and Nb2O5 leads to oxygen vacancy and enhanced electronic conductivity. The sodium storage performance of S‐Nb2O5 HNS@S‐rGO is unprecedented. It delivers a reversible capacity 215 mAh g−1 at 0.5 C over 100 cycles. In addition, it also possesses a great high‐rate capability, retaining a stable capacity of 100 mAh g−1 at 20 C after 3000 cycles. This design demonstrates the potential applications of Nb2O5 as anode for high performance NIBs. [ABSTRACT FROM AUTHOR]

The structure of orthorhombic lysozyme has been obtained at 298 K and pH 4.5 using sodium chloride as the precipitant and in the presence of sodium phosphate at a concentration as low as 5 mM. Crystals belonging to space group P212121 (unit‐cell parameters a = 30, b = 56, c = 73 Å, α = β = γ = 90.00°) diffracted to a resolution higher than 1 Å, and the high quality of these crystals permitted the identification of a phosphate ion bound to Arg14 and His15. The binding of this ion produces long‐range conformational changes affecting the loop containing Ser60–Asn74. The negatively charged phosphate ion shields the electrostatic repulsion of the positively charged arginine and histidine residues, resulting in higher stability of the phosphate‐bound lysozyme. Additionally, a low‐humidity orthorhombic variant was obtained at pH 4.5, and comparison with those previously obtained at pH 6.5 and 9.5 shows a 1.5 Å displacement of the fifth α‐helix towards the active‐site cavity, which might be relevant to protein function. Since lysozyme is broadly used as a model protein in studies related to protein crystallization and amyloid formation, these results indicate that the interaction of some anions must be considered when analysing experiments performed at acidic pH values. [ABSTRACT FROM AUTHOR]