Supramolecular structure of S-(+)-marmesin—a linear dihydrofuranocoumarin

The title compound, C₁₄H₁₄O₄, a linear dihydrofuranocoumarin, was isolated from the bark ofAegle marmelos, a plant widely used in Ayurvedic system of medicine for the treatment of various ailments. The crystal structure was determined from X-ray diffraction data using direct methods. The compound crystallizes into monoclinic space group P2₁ with unit cell parameters:a] = 5.721(1) Å, b= 13.810(1) Å, c= 7.864(2) Å, β = 100.39(1)°, Z = 2. The structure was refined by full-matrix least-squares to a finalR value of 0.0523 for 1184 observed reflections. The benzopyran moiety is perfectly planar. The dihedral angle between the pyrone and benzene rings is 0.3(1)°. The furan ring has a 2α-envelope conformation. The molecules are linked by O-H…O hydrogen bonds into chains and these chains are linked into sheets by C-H…O hydrogen bonds. Further, the π-π stacking and C-H…π (arene) interactions link all of the sheets into a supramolecular structure.     

Hybrid open frameworks: Hydrothermal synthesis and structure determination of MIL-33: a new vanadomethylendiphosphonate intercalating potassium cations

The hydrothermal synthesis and the ab initio structure determination from powder data of K₂(V^VO₂)₄(V^IVO){O₃P–CH₂–PO₃}₂–xH₂O (x=4) or MIL-33 are presented. MIL-33 crystallizes in the monoclinic system [space group C2/m (No. 12)] with lattice parameters a=4.8716(4) Å, b=14.614(1) Å, c=15.825(1) Å, β=94.06(1) Å, V=1123.8(2) ų, Z=2. MIL-33 is a mixed valence V^IV/V^V=1/4 vanadodiphosphonate. Its layered structure shows some potassium cations located both between the hybrid layers and in the eight-membered windows of the latter.     

Synthesis and structure of a new cobalt-containing aluminophosphate

We report on the synthesis and single-crystal structure of a novel cobalt-substituted aluminophosphate. Crystal data: monoclinic, space group $\text{P2}{}_1\text{c}$ (no. 14), a = 8.593(1), b = 15.540(1), c = 7.736(1)Å, β = 110.65(1)°, V = 966.7(4)ų, Z = 4, R = 0.037, and R_w = 0.029 for 2280 contributing reflections and 182 variables. Refined framework-atom bond distances and angles exhibited regular tetrahedral coordination of Al and P [d_ave(AlO) = 1.74(1)Å, d_ave(PO) = 1.54(2)Å] and distorted Co-centered octahedra. The Co substituted every second aluminum in the ordered AlP distribution and was coordinated to five framework oxygen atoms and to one nitrogen atom from a template ethylenediamine molecule located in an eight-member ring opening. Structure collapsed in the absence of template.     

Molecular and supramolecular structure of 4,4'-bipyridinium diiodide

The structure of 4,4'-bipyridinium diiodide has been determined. The diprotonated cation possesses crystallographic inversion symmetry with the pyridyl rings coplanar. The crystal packing is dominated by weak but directional N-H⋯I (N⋯I distance of 3.47(2) Å) and C-H⋯I (C⋯I distances of 3.74(3)3.77(3) Å) interactions to give layers of ions. The layers stack parallel to the (101) direction and are linked together by an additional C-H⋯I interaction (C⋯I distance of 3.816(5) Å). Crystal data: triclinic, P-1 (No. 2), a = 8.2940(13), b = 8.3842(11), c = 5.0978(8) Å, α = 93.761(11)°, β = 112.281(12)°, γ = 106.887(11)°, V = 307.63(8) ų, Z = 1, D_calc = 2.22 g/cm³. Final residual values based on 997 observed (I>2σ(I)) reflections: R = 0.026, R_w, = 0.034.     

Crystal structure and magnetic properties of CuSb2O4

The crystal structure of a copper antimonite (CuSb₂O₄) was determined from X-ray powder diffraction data. The structure was solved by simulated annealing in direct space using the Rietveld method. The compound crystallizes in tetragonal symmetry and space group P4 ₂ bc (106); unit cell parameters a = b = 8.76033(5) Å, c = 5.79786(4) Å, Z = 4, V = 444.947(5) Å³ and density (calc.) = 5.539 g cm^?3. The CuO₆ polyhedra are strongly elongated due to Jahn–Teller distortion in a [2+2+2] coordination arrangement, i.e. there are two long axial Cu–O1 bonds of 2.447(13) Å and in the equatorial plane there are two intermediate Cu–O2 bonds of 2.07(3) Å and two short Cu–O2 bonds of 1.88(2) Å. The SbO₃ pyramidal arrangement is almost regular with Sb–O1 bonds of 1.97(2) Å (2×) and Sb–O2 of 1.959(5) Å. The experimentally obtained Raman spectrum is consistent with values obtained from theoretical modelling studies. The magnetic behaviour of this new compound suggests that it belongs to the class of S = 1/2 Heisenberg chain systems.     

Hydrothermal synthesis, structure and characterization of new NASICON related potassium iron (III) pyrophosphate

A new potassium iron (III) pyrophosphate was synthesized by hydrothermal technique and characterized by X-ray studies. The compound crystallizes in a monoclinic space group,P2 ₁/c, with cell parameters,a = 7 365(2) Å,b = 10017(2) Å,c = 8.214(1) Å,β = 106.50(1)° andZ = 4. The structure has tunnel-type cavities and are congenial for ion transportation through them. The compound exhibits moderate thermal stability.     

Electronic structure and possible martensitic transformation in Ni2FeIn alloy

The electronic structure and magnetic properties of Heusler alloys (Ni₂FeIn) have been studied by first principle calculations. The possible tetragonal martensitic transformation has been predicted and the structure optimization was made on cubic austenitic Ni₂FeIn in Cu₂MnAl type. The equilibrium lattice constant of austenitic Ni₂FeIn is 6.03 Å. In tetragonal phase, the global energy minimum occurs at c/a = 1.29. The corresponding equilibrium lattice constants for martensite Ni₂FeIn are a = b = 5.5393 Å and c = 7.1457 Å, respectively. In the austenitic phase, E _F is located at the peak in the minority DOS for c/a = 0.96 to 1.20, but in the martensitic phase, E _F moves to the bottom of the valley in the minority DOS, reducing the value of N(E _F ) effectively. Both austenitic and martensitic phases are ferromagnetic and the Ni and Fe partial moments contribute mainly to the total moments. Therefore, the martensitic transformation behavior in Ni₂FeIn is predicted.     

Synthesis,crystal structure,thermal analysis and dielectric properties of two mixed trichlorocadmiates (II)

K_0.57(NH₄) _0.43CdCl₃ and K_0.25(NH₄) _0.75CdCl₃ are orthorhombic, space group Pnma, Z = 4, with a = 8.8760(4) Å, b = 3.9941(2) Å, c = 14.7004(7) Å, and Z = 4, a = 8.9567(9) Å, b = 3.9957(4) Å, c = 14.855 (2) Å, respectively. Final R values are 0.01 and 0.02 for 608 and 834 reflections, respectively. In both the materials, the crystal structure has been determined by X-ray single crystal analysis at room temperature (293 K). The compound structures consist of K⁺ (or NH\(_{{4}}^{{+}})\) cations and double chains of CdCl₆ octahedra sharing one edge extending along b-axis. The mixture of K⁺/NH\(_{{4}}^{{+}}\) cations are located between the double chains ensuring the stability of the structure by ionic and hydrogen bonding contacts N/K–H …Cl. Spectroscopic, dielectric and differential scanning calorimetry (DSC) measurements were performed to discuss the mechanism of the phase transition. These studies show that these materials, K_0.57(NH₄)_0.43CdCl₃and K_0.25(NH₄)_0.75CdCl₃, undergo a phase transition at 438 and 454 K, respectively.     

Preparation and crystal structure characterization of CuNiGaSe<Subscript>3</Subscript> and CuNiInSe<Subscript>3</Subscript> quaternary compounds

Samples of the quaternary chalcogenide compounds, CuNiGaSe₃ and CuNiInSe₃, prepared by direct fusion and annealing method, were characterized by X-ray powder diffraction. In each case, the crystal structure was refined using the Rietveld method. Both compounds were found to crystallize in the tetragonal system, space group P \(\bar 4\)2c (N°112), with unit cell parameter values a = 5.6213(1) Å, c = 11.0282(3) Å, V = 348.48(1) ų and a = 5.7857(2) Å, c = 11.6287(5) Å, V = 389.26(3) ų for CuNiGaSe₃ and CuNiInSe₃, respectively. These compounds have a normal adamantane structures and are isostructural with CuFeInSe₃.     

Supramolecular templates for the synthesis of new nanostructured uranyl compounds: Crystal structure of [NH3(CH2)9NH3][(UO2)(SeO4)(SeO2OH)](NO3)

Crystals of a new uranyl selenate, [NH₃(CH₂)₉NH₃][(UO₂)(SeO₄)(SeO₂OH)](NO₃) (1), were prepared by isothermal evaporation from aqueous solution at room temperature. The crystal structure was solved by the direct method $ P\bar 1 $ , a = 10.7480(7), b = 13.8847(9), c = 14.6363(10) Å, α = 109.9600(10)°, β = 103.212(2)°, γ = 90.4090(10)°, V = 1990.0(2) ų, Z= 4) and refined to R ₁ = 0.0379 (wR ₂ = 0.0636) for 8515 reflections with ¦Fo¦ ≥ 4σ_F. The structure is based on [(UO₂)(SeO₄)(SeO₂OH)]-layers parallel to the (001) plane. In the structure of 1, there are two crystallographically independent 1,9-diammoniononane cations forming micelles in which the hydrocarbon chains are packed crosswise. The micelles are cylinders with an elliptical cross section and a rough surface. They are organized by the principle of hydrophilic and hydrophobic interactions. The cylinders are separated from each other by layers of triangular NO ₃ ^? groups. Compound 1 is an example of organic-inorganic composites with a unidimensional organic substructure in which the protonated chain-like diamine molecules arranged crosswise form cylindrical supramolecular templates.     

Explosive crystallization in the course of formation of Se/Ag nanosize film structure

Results of an experimental study of explosive crystallization appearing in the process of formation of a Se/Ag nanosize film structure are presented. It is shown that explosive crystallization appears in a wide range of Se film thicknesses (70–280 nm) and occurs during a narrow time interval (2.00–4.52 s). The cooperative effect of the thermal energy of the phase transformation of Ag₂Se and the energy of elastic stress in the amorphous Se film leads to development of an explosive crystallization. It was found that, depending on the relative thicknesses of Se and Ag films, orthorhombic Ag₂Se with crystal-lattice constants a = 4.333 Å, b = 7.062 Å, and c = 7.764 Å and hexagonal Se (a = 4.3552 Å and c = 4.9495 Å) are formed in the reaction products upon the explosive crystallization.     

Synthesis and characterization of ternary compound,Mn<Subscript>2</Subscript>SnTe<Subscript>4</Subscript>

Mn₂SnTe₄ was synthesized by direct fusion using the anneal method. X-ray powder diffraction analysis indicated that this material crystallizes in the olivine-type structure, space group Pnma, Z = 4, with unit cell parameters: a = 14.020(2) Å, b = 8.147(1) Å, c = 6.607(1) Å, V = 754.7(2) ų. The Rietveld refinement converged to the figures of merit, R _p = 6.9%, R _wp = 8.5%, R _exp = 6.0%, χ² = 2.0 and S = 1.4.     

Phase equilibria in the Tl2MoO4-Pr2(MoO4)3-Hf(MoO4)2 system and crystal structure of TlPr(MoO4)2

Subsolidus (450–480°C) phase relations in the Tl₂MoO₄-Pr₂(MoO₄)₃-Hf(MoO₄)₂ system have been studied by X-ray diffraction. The system has been shown to contain molybdates with the compositions Tl₅PrHf(MoO₄)₆ (5: 1: 2), TlPrHf_0.5(MoO₄)₃ (1: 1: 1), and Tl₂PrHf₂(MoO₄)_6.5 (2: 1: 4). Single crystals of the double molybdate TlPr(MoO₄)₂ have been grown for the first time from high-temperature solutions through spontaneous nucleation, and their crystal structure has been determined: tetragonal symmetry, sp. gr. P4/nnc, a = 6.3170(1) Å, c = 9.5529(2) Å, V = 381.204(12) ų, Z = 2.     

Synthesis and crystal structure of a uranyl bichromate, [CH6N3]2[(UO2)(CrO4)(Cr2O7)](H2O)

Crystals of the first uranyl bichromate, [CH₆N₃]₂[(UO₂)(CrO₄)(Cr₂O₇)](H₂O), were obtained by evaporation from aqueous solutions. The compound crystallizes in the triclinic system, space group $P\bar 1$ , a = 7.1829(17), b = 9.304(3), c = 14.884(4) Å, α = 102.43(2)°, β = 97.98(2)°, γ = 101.07(2)°, V = 936.3(5) ų, Z = 2. The structure was solved by direct methods and refined by the full-matrix least-squares method to R ₁ = 0.064 (wR ₂ = 0.138) for 2225 reflections with |F _hkl | ≥ 4σ(|F _hkl |). The structure is based on infinite [(UO₂)(CrO₄)(Cr₂O₇)]^2? chains where [UO₇]^8? pentagonal bipyramids are linked by tridentate [Cr(1)O₄]^2? groups and [Cr₂O₇]^2? groups; these chains run along x axis and are oriented parallel to $(0\bar 11)$ . Trigonal [CH₆N₃]⁺ cations and water molecules are arranged between the chains.     

V<Subscript>3.047</Subscript>O<Subscript>7</Subscript>, a new high-pressure oxide with the simpsonite structure

Reaction between α-V₂O₅ and NaN₃ has been studied at pressures from 5.0 to 6.0 GPa and temperatures from 600 to 800°C using Toroid high-pressure chambers. A new oxide, V_3.047O₇ (VO_2.297), isostructural with simpsonite, Al₄Ta₃O₁₃(OH), has been detected in samples with the initial composition 0.2NaN₃ · V₂O₅ after high-temperature, high-pressure processing at p = 5.0 GPa and t = 800°C for 2 min. The crystal structure of the oxide has been refined by the Rietveld method using X-ray powder diffraction data: a = 7.35136(2) Å, c = 4.51462(2) Å, V = 211.294(1) ų, Z = 2, sp. gr. P3. Each vanadium atom in this structure is coordinated by six oxygens in the form of a [VO₆] octahedron. The synthesized oxide is a second compound with the simpsonite structure. We have measured the infrared transmission and Raman spectra of V_3.047O₇. Electrical measurements have demonstrated that the material is a semiconductor.     

Compounds WAl<Subscript>4</Subscript>, WAl<Subscript>3</Subscript>, W<Subscript>3</Subscript>Al<Subscript>7</Subscript>, and WAl<Subscript>2</Subscript> and Al-W-N combustion products

X-ray diffraction data are presented for combustion products in the Al-W-N system. New, nonequilibrium intermetallic compounds have been identified, their diffraction patterns have been indexed, and their unit-cell parameters have been determined. The phases α-and β-WAl₄ are shown to exist in three isomorphous forms, differing in unit-cell centering. The phases α′-, α″-, and α?-WAl₄ are monoclinic, with a ₀ = 5.272 Å, b ₀ = 17.770 Å, c ₀ = 5.218 Å, β = 100.10°; point groups C12/c1, A12/n1, I12/a1, respectively. The phases β′-, β″-, and β?-WAl₄ are monoclinic, with a ₀ = 5.465 Å, b ₀ = 12.814 Å, c ₀ = 5.428 Å, β = 105.92°; point groups A112/m, B112/m, I112/m, respectively. The compounds WAl₂ and W₃Al₇, identified each in two isomorphous forms, differ in cell metrics (doubling) but possess the same point group: P222. WAl ₂ ^′ : orthorhombic, a ₀ = 5.793 Å, b ₀ = 3.740 Å, c ₀ = 6.852 Å. WAl ₂ ^″ : orthorhombic, a ₀ = 11.586 Å, b ₀ = 3.740 Å, c ₀ = 6.852 Å. W₃Al ₇ ^′ : orthorhombic, Pmm2, a ₀ = 6.225 Å, b ₀ = 4.806 Å, c ₀ = 4.437 Å. W₃Al ₇ ^″ : orthorhombic, Pmm2, a ₀ = 12.500 Å, b ₀ = 4.806 Å, c ₀ = 8.874 Å. The new phase WAl₃: triclinic, P1, a ₀ = 8.642 Å, b ₀ = 10.872 Å, c ₀ = 5.478 Å, α = 104.02°, β = 64.90°, γ = 107.15°.     

Crystal structure of NdLiP4O12

A single-crystal x-ray diffraction analysis has been performed on NdLiP₄O₁₂ synthesized by a flux method. The structure is monoclinic, with space group C 2/c, Z = 4, and cell parameters a = 16.408 (3), b = 7.035 (4), $\text{c}\text{= 9.729 (4)}\text{A}\text{?}$, and β = 126.38 (5)°. A full-matrix, least squares refinement gave R = 0.072, Rw = 0.077 for 590 independent reflections. The basic structural units are helical ribbons, (PO₃)_n, formed by corner-sharing of PO₄ tetrahedra. The NdO₈ dodecahedra are isolated from each other in the sense that they do not share any O atoms. This isolation accounts for the marked reduction in the concentration quenching of Nd⁺³ fluorescence that is observed for NdLiP₄O₁₂. The shortest Nd-Nd distance is 5.620 Å, and the concentration of Nd⁺³ ions is 4.42 × 10²¹ cm^?3     

Magnetization, magnetic susceptibility, and effective magnetic moment of the Fe3+ ions in Bi2Fe4O9

Bi₂Fe₄O₉ with an orthorhombic structure and lattice parameters a = 7.9595 Å, b = 8.4297 Å, c = 5.9912 Å, and V = 401.987 ų has been prepared by solid-state reactions method. Its molar magnetic susceptibility measured as a function of temperature in the range 5–950 K indicates that Bi₂Fe₄O₉ is an antiferromagnet with a Néel temperature of 258 K. In the range 280–750 K, its molar magnetic susceptibility exhibits Curie-Weiss behavior, which allowed us to determine the Weiss constant (Θ = ?1468 K) of this material and the effective magnetic moment of the Fe³⁺ ions $\left( {\mu _{eff}^{Fe^{3 + } } = 6.37\mu _B } \right)$ . Magnetization versus magnetic field data show no magnetic hysteresis, indicating that the Bi₂Fe₄O₉ sample studied exhibits no weak ferromagnetism.     

Synthesis, structure, and properties of [Be(H2O)4][UO2(CH3COO)3]2

Crystals of previously unknown compound [Be(H₂O)₄][UO₂(CH₃COO)₃]₂ were prepared and studied by X-ray diffraction analysis. The compound crystallizes in the tetragonal system, unit cell parameters (at 100 K): a = 10.3647(3), c = 23.4127(8) Å, V = 2515.16(13) ų, space group I4₁/a, Z = 4, R = 0.0194. The structure consists of mononuclear complexes [Be(H₂O)₄]²⁺ and [UO₂(CH₃COO)₃]^? linked with each other by electrostatic interactions and hydrogen bonds formed by water molecules and O atoms of acetate anions. The compound was also studied by methods of thermal analysis and IR spectroscopy.     

High-pressure,high-temperature study of GeS2 and GeSe2

Phase transitions of the GeX₂ (X = S, Se) dichalcogenides have been studied at pressures of up to p ? 8 GPa and temperatures from 675 to 1375 K, and portions of their p-T phase diagrams have been constructed using our and previous experimental data. The crystal structure of the GeS₂-III phase has been refined by the Rietveld method (HgI₂ structure, P4₂/nmc, a = 3.46906(2) Å, c = 10.9745(1) Å, Z = 2, D _x = 3.438 g/cm³, R = 0.06). GeSe₂-III crystals have been grown for the first time at p ? 7 GPa in the temperature range 875–1275 K. The unit-cell parameters of GeSe₂-III (hex) are a = 6.468 ± 0.004 Å and c = 24.49 ± 0.10 Å (D _meas = 5.16 g/cm³, D _x = 5.18 g/cm³, Z = 12).