α-Li3InF6, a ternary fluoride with a new structure type

Reaction of anhydrous binary fluorides LiF and InF₃ in sealed platinum tube at the temperature gradient 680/670°C yields α-Li₃InF₆. This low-temperature form crystallizes in the space group P2₁/m with the cell dimensions a = 4.797(3) Å, b = 8.679(1) Å, c = 10.366(1) Å and β = 90.90(1)°. The framework is built from InF₆ and LiF₆ octahedra, beside [Li₂F₆] bitetrahedra. The b-axis seems to be the backbone in the structural features. Running along it, zigzag anionic chains , resulting from one—edge shared [Li₂F₁₀] groups and double files of single InF₆ octahedra sharing common corners with [Li₂F₆], create an approximately hexagonally packed framework in the plane (1 0 0). The antiferroelectric behaviour evident from dielectric studies is confirmed by the antiparallel displacements of In and Li atoms from octahedral centres. This structure is mainly featured by the disorder observed in the lightest atoms. These atoms, which exhibit two kinds of environments, have been refined as two partially occupied sites for the tetrahedral one. Within the Li₃MF₆ compounds (M: trivalent or 3d element), this new structure reveals unexpected structural features, inducing its ferroic properties.     

Structures of 8α-(2′-methylbutyryloxy)-9α-hydroxymontahibisciolide,a new skeletal type of sesquiterpene lactone,and of its precursor 8α-isobutyryloxy-9-oxo-germacra-4E, 1(10)Z-dien-6β,12-olide

The structures of a new skeletal type of sesquiterpene lactone, containing a seven, five, fivering system, and of its putative precursor, a 9-oxo-melampolide, have been confirmed by single crystal X-ray structure determination. The central 5-membered ring of the new skeleton istrans-fused to the cycloheptene ring andcis-fused to the lactone ring. Transannular interactions and the geometry of thetrans carbon-carbon double bond of the oxo-melampolide and the keto-group at C9, suggest that the new seven, five, five tricyclic skeleton-type of montahibisciolide can easily be reached by a transannular cyclization process. The isobutyrloxy group of the oxo-melampolide is disordered into two partially populated conformations. 8-(2-Methylbutyryloxy)-9-hydroxymontahibisciolide,3, C₂₀H₂₈O₅, crystallizes in orthorhombic space groupP2₁2₁2₁ witha=8.294(2),b=9.740(2),c=22.675(1) Å,V=1832(1)ų,Z=4. The structure was refined toR=0.043 andR _w=0.048 for 2898 observed reflections with CuK radiation. 8-isobutyryloxy-9-oxo-germacra-4E, 1(10)Z-dien-6, 12-olide,4, C₁₉H₂₄O₅, crystallizes in monoclinic space groupC2 witha=32.879(7),b=5.793(2),c=9.884(4)Å, =99.01(3)°,V=1859.5(9)å³,Z=4. The structure was refined toR=0.054 andR _w=0.064 for 1010 observed reflections with MoK radiation.     

Bismuth a new dopant for GaN films grown by molecular beam epitaxy—surfactant effects,formation of GaN1−xBix alloys and co-doping with arsenic

We have investigated the influence of an additional bismuth flux during growth on the properties of GaN films prepared by plasma-assisted molecular beam epitaxy (MBE). A wide range of bismuth fluxes have been used, the highest Bi flux was larger than the flux of Ga. We have demonstrated that using a Bi flux during the growth of GaN by MBE at a temperature ∼800°C improves the surface morphology of the films and decreases the deep emission. We have demonstrated for the first time the growth of GaN_1−xBi_x alloys by MBE, the Bi concentration was small and increased with decreasing growth temperature. We have studied the influence of an additional bismuth flux on the growth of As-doped GaN layers and observed an increase of blue emission from the layers at some optimum range of Bi fluxes. All the results allow us to conclude that Bi may be a potential new dopant for the growth of GaN by MBE.     

Optical properties of new low-phonon SnF2–PbF2–ZnF2 glasses

New fluoride glasses were developed in the SnF₂–PbF₂–ZnF₂ system. Additions of 5 mol% of CsCl or 6–15 mol% of AlF₃ were found to stabilize the glass formation. The IR absorption of the glasses and the optical properties of the europium ions doped in the glasses were compared with those of a fluorozirconate glass as a representative fluoride glass. The IR spectra showed that the new glasses have the peak of the phonon energy at 400 cm⁻¹, which is about 100 cm⁻¹ lower than that of the fluorozirconate glass. The results of the fluorescence measurement of the europium ions revealed that the multi-phonon relaxation rate in these glasses is smaller than that in the fluorozirconate glass.     

Crystal structure,vibrational spectra and thermal decomposition study of a new,dicationic, acidic pyrophosphate: KHMgP<Subscript>2</Subscript>O<Subscript>7</Subscript>⋅2H<Subscript>2</Subscript>O

Colourless crystals of a new, dicationic, hydropyrophosphate dihydrate salt, KHMgP₂O₇⋅ 2H₂O, are formed, when a mixture of aqueous equimolar solutions of MgCl₂⋅4H₂O and K₄P₂O₇, at pH 2.12, are left to stand at ambient temperature for 4 days. The new pyrophosphate salt has been characterized by single-crystal X-ray diffraction, IR and Raman spectra, and DSC-TG thermal analysis. The structure consists of alternating layers of [HP₂O₇]³⁻ groups and MgO₆ octahedra, joined by K⁺ ions and bridging hydrogen bonds. The [P₂O₇]⁴⁻ anions exhibit a bent eclipsed conformation. The absence of coincidences for the majority of the IR and Raman bands is in accord with the centrosymmetric structure of the material. The ³¹P chemical shift tensor components have been determined from the solid-state MAS NMR spectra. The structural changes occurring during thermal decomposition have been examined by TG-DSC, X-ray powder diffraction (XRD) and IR spectroscopy. When the new pyrophosphate salt is heated gradually, it first becomes amorphous and then condenses to chain metaphosphates.     

K8Gd3Si12O32Cl · 2H2O,a new member of the family of porous silicates with K and RE elements

Crystals of K₈Gd₃Si₁₂O₃₂Cl · 2H₂O (space group $P\bar 1$ ), a new member of the family of porous silicates containing rare earths, are obtained under hydrothermal conditions. The structure retains the main features of the family in which original one-story layers of Si-tetrahedra formed by 6-membered rings of two types and large-in-diameter 8-membered and 12-membered rings are bound by Gd-octahedra to form a framework. Large pores in the interlayer space of the mixed framework are filled with K⁺ ions. The penetration of Cl^? ions from a concentrated mineralizing solution into the centers of the eight-membered rings of the layer corroborates the ion-exchanging properties of the crystals of this structural type. The filling of rings and pores of different types in different members of the family by K⁺ and Cl^? ions, hydroxyl groups, and water molecules is analyzed.     

Intermetallic Compounds KnMm (М = Ag,Au, As,Sb, Bi,Ge, Sn,Pb): Geometrical and Topological Analysis,Cluster Precursors,and Self-Assembly of Crystal Structures

Crystallography Reports - A geometrical and topological analysis and simulation of the self-assembly of the crystal structures of intermetallic compounds formed in the K–M (M = Ag, Au, As,...     

繁荣学术,服务产业,正五十,再出发

<正>疫情蔓延却挡不住时代悦动的脉搏,随着2022年新春钟声的敲响,《人工晶体学报》也迎来了创刊50周年。20世纪60年代后期,位于北京郊区的原国家建材局人工晶体研究所为了方便所内技术交流,创办了内部刊物《人工晶体译丛》,主要刊载所内技术人员翻译的国外相关领域最新进展。到1972年,期刊刊登范围逐步扩大,陆续刊出所内研究简报、研究论文等,同时也报道国内相关团队的研究近况,遂更名《人工晶体》。时值我国国防工业建设高潮,与国防工业关系密切的人工晶体材料正取得日新月异的发展,水晶、金刚石、云母三大合成晶体相继研发成功并走向市场,激光晶体、非线性光学晶体、闪烁晶体、压电晶体等一大批晶体合成成功,晶体界急需一本自己的专业期刊方便国内同行的交流。在老一辈晶体专家吴乾章等的共同倡议和努力下,《人工晶体》确定为中国硅酸盐学会晶体生长与材料专业委员会的代表会刊,从此走上时代舞台,肩负起传播中国晶体文化,引领中国晶体科技发展的历史使命。1989年,《人工晶体》更名《人工晶体学报》。     

Syntheses and structures of two new organic–inorganic hybrid lanthanide derivatives based on Keggin-type polyoxometalates

Two new organic–inorganic hybrid Keggin-type polyoxometalates containing lanth-anide(III) cations with 3D supramolecular framework structures, [La(DMSO)₈][PW₁₂O₄₀] (1) and [La(DMSO)₈][PMo₁₂O₄₀] (2) (DMSO = dimethyl sulfoxide), have been synthesized in aqueous solution under moderate conditions and further characterized by elemental analysis, inductively coupled plasma (ICP) analyses, IR spectroscopy, electronic spectra, thermogravimetric analysis, and single-crystal X-ray diffraction analyses. The title complexes exhibit similar 3D supramolecular frameworks directed by the different hydrogen bonding interactions. The TG curve exhibit the weight loss of complex 1, which can be divided into five stages, suggesting that the intensity of coordination bonds are different between La(III) and DMSO molecules.     

First crystal structure of a pentacyclic biomarker: 4,4,6a,12b,14b-Pentamethyl-1,2,3,4,4a,5,6,6a,6b,7, 8,12b,13,14,14a,14b-hexadecahydropicen-3β-ol

The crystal structure of the title compound (1, C₂₇H₄₀O 1/8 H₂O) synthesized via photo-induced electron transfer promoted biomimetic cascade cyclization, is reported. Compound 1 crystallizes in the monoclinic space group C2/c, with cell parameters a = 53.982(4), b = 7.1889(6), c = 11.170(1) Å, = 96.86(1). The structure adopts a fully trans-fused ring junction with all methyl groups axially oriented. The geometrical aspects associated with 1 were discussed and compared with the previously determined X-ray data for structurally analogous compounds.     

Crystal structure of a new double salt hydrate SrCd2Cl6⋅8H2O

SrCd₂Cl₆8H₂O crystallizes in the space group and has the unit cell dimensions a = 9.688(2) Å, b = 11.212(2) Å, c = 7.732(3) Å, = 99.85(21)°, = 89.95(22)°, = 75.81(13)°, and Z = 2. After refinement through full-matrix least-squares methods, the reliability factor R in the final cycle is 4.65%. A very persistent occurrence of twinning by pseudosymmetry was observed. The twin element is a twofold axis [001]. The title compound exhibits five endothermic peaks, which have been detected by differential scanning calorimetry and interpreted from thermogravimetry.     

Crystal structure and spectroscopy of a new dmg2−-bridged dinuclear cobalt(III) compound

A new dinuclear complex of formula [Co₂(dien)₂(dmg)₂](ClO₄)₂4.5H₂O (dien = diethlyenetriamine, dmg^2– = dianion of dimethylglyoxime) has been synthesized and characterized by single crystal X-ray diffraction analysis. It crystallizes in the monoclinic space group c2/c, with a = 20.868(7) Å, b = 11.408(4) Å, c = 15.816(4) Å, = 116.97(2), V = 3355.8(17) ų, Z = 4, F(000) = 1732. The structure consists of a dmg^2–-bridged Co(III) dimer. The coordination environments of two Co(III) ions are identical. Each cobalt(III) ion is coordinated by five nitrogen of one dien molecule and one dmg^2– ligand, and the coordination sphere is completed by an oxygen atom of the bridging dmg^2–. The compound is characterized by means of room temperature magnetic susceptibility measurement and infrared spectroscopy.     

Potassium bromo-borate K3[B6O10]Br—A new nonlinear optical material

A new polar hexaborate, K₃[B₆O₁₀]Br (space group R3m), is synthesized under hydrothermal conditions. The radical anion is composed of macallisterite hexaborate blocks 6[3Δ + 3T] formed by boron triangles and boron tetrahedra. The blocks are joined together through vertices into a [B₆O₁₀] _∞∞∞ ^2? zeolite-like framework of a new type. Large K⁺ cations and Br^? anions are located in extended channels that are aligned parallel to rhombohedral translations of the crystal lattice. The structure of the sublattice formed by large ions consists of BrK₆ bromo-centered octahedra, which are linked together through vertices into a hexagonally distorted perovskite framework. The perovskite framework is inserted into the boron-oxygen framework so that these two frameworks do not intersect. The nonlinear optical properties of powdered samples of the K₃[B₆O₁₀]Br compound are investigated using the second harmonic generation method. It is found that the K₃[B₆O₁₀]Br compound exhibits a high nonlinear optical activity that exceeds the activities of the majority of borate compounds and is characteristic of haloid borates of the hilgardite family.     

Electronic Properties,Reactivity, Flexibility,Polarity, Thermodynamic Properties,and Dynamic Simulation of a Series of Hybrid Organic–Inorganic Polyoxoselenomolybdate Compounds

Crystallography Reports - A large theoretical study of three hybrid inorganic-organic polyoxoselenomolybdate-based systems (C7H10N)4[Se2Mo5O21]⋅5H2O (1), (C6H8N)4[Se2Mo5O21]⋅7H2O (2)...     

Synthesis,structure, spectroscopic investigations,and computational studies of optically pure β-ketoamide

Chemical preparation, X-ray single crystal diffraction, IR and NMR spectroscopic investigations of a novel nonlinear optical organic compound (C₁₇H₂₂NO₂Cl) are described. The compound crystallizes in the orthorhombic system with the non-centrosymmetric sp. gr. P2₁2₁2₁. In the crystal structure, molecules are interconnected by N–H…O hydrogen bonds forming infinite chains along a axis. The Hirshfeld surface and associated fingerprint plots of the compound are presented to explore the nature of intermolecular interactions and their relative contributions in building the solid-state architecture. The molecular HOMO–LUMO compositions and their respective energy gaps are also drawn to explain the activity of the compound. The first hyperpolarizability β_tot of the title compound is determined using DFT calculations. The optical properties are also investigated by UV–Vis absorption spectrum.     

Structure of a new crystal modification of the bacterial NAD-dependent formate dehydrogenase with a resolution of 2.1 Å

Formate dehydrogenase (FDG) from methylotrophic bacteria Pseudomonas sp. 101 catalyzes the reaction of oxidation of the formate ion to carbon dioxide, which is accompanied by the reduction of nicotinamid adenine dinucleotide (NAD⁺). The structures of the apo and holo (enzyme-NAD-azide triple complex) forms of the enzyme were determined earlier. In an attempt to prepare a complex of FDG with the product of the enzymatic reaction (NADH), a new crystal modification of FDG is obtained (space group P4₂2₁2, a = b = 93.3 Å, c = 103.05 Å). The FDG structure is solved by the molecular replacement method and refined to R = 20.7%. The asymmetric part of the unit cell contains one FDG molecule. In contrast to the previously studied FDG structures, the biologically active dimer is formed by the crystallographic rotation axis. A comparative structural analysis of the studied form with the apo and holo forms of the enzyme is performed. The influence of the molecular structure on the environment in the crystal is investigated.     

Synthesis and structural evidence for new diimidazo-[1,5-a:1′,5′-d] pyrazinediones

The synthesis of derivatives of 5H, 10H-diimidazo [1,5-a:l,5-d] pyrazine-5,10-dione is described. The mechanism of the reaction is discussed and the chemical, spectral and X-ray data giving the evidence of the structure of these compounds are presented. X-ray studies were carried out on compound6c (C₂₄H₂₂N₆O₂) witha=9.250(3),b=11.879(3),c=10.250(3),Z=2 and space groupP2₁/a. The structure was solved using direct methods and refined by weighted full-matrix least squares. The refinement, based on 990 reflections withI2.5(I), converged to a finalR of 0.041 andR _w=0.036.     

Synthesis,Crystal Structure,Antioxidant, and α-Glucosidase Inhibitory Activities of Methoxy-substituted Benzohydrazide Derivatives

Eight methoxy substituted at the benzylidene moiety benzohydrazide derivatives [R = 2-OCH₃ (1), 3-OCH₃ (2), 4-OCH₃ (3), 2,3-(OCH₃)₂ (4), 3,4-(OCH₃)₂ (5), 2,4,5-(OCH₃)₃ (6), 2,4,6-(OCH₃)₃ (7), and 3,4,5-(OCH₃)₃ (8)] were synthesized and characterized by ¹H NMR, FT-IR and UV-Vis spectroscopy. The crystal structure of 4 was determined by single crystal X-ray diffraction (sp. gr. Pbca, Z = 8). The molecule is slightly twisted with the dihedral angle between the two phenyl rings being 9.33(14)°. The methoxy group at the ortho position is twisted [C–O–C–C angle is–109.2(3)°] whereas the other at meta position is co-planar with the attached benzene ring. In the crystal packing, the molecules are linked into two-dimensional network parallel to the (001) plane by O–H···O, O–H···N, and N–H···O hydrogen bonds. Compounds 1–8 were evaluated for an antioxidant and α-glucosidase inhibitory activities and the results suggested that the ?OCH₃ substituent was ineffective for bioactivity enhancement.