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°.     

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.     

High-temperature crystal chemistry of Na<Subscript>6</Subscript>(UO<Subscript>2</Subscript>)<Subscript>2</Subscript>O(MoO<Subscript>4</Subscript>)<Subscript>4</Subscript>

Thermal deformations of Na₆(UO₂)₂O(MoO₄)₄ were studied by high-temperature powder X-ray diffraction. The compound crystallizes in the triclinic system, space group Р\(\bar 1\), a = 7.636(7), b = 8.163(6), c = 8.746(4) Å, α = 72.32(9)°, β = 79.36(4)°, γ = 65.79(5)°, V = 472.74(4) ų. It is stable in the temperature interval 20–700°С. The thermal expansion coefficients (TECs) are α₁₁ = 25.5 × 10^–6, α₂₂ = 7.8 × 10^–6, and α₃₃ = 1.1 × 10^–6 (°C)^–1. The orientation of the TEC pattern relative to the crystallographic axes is a₃₃^Z = 45°, a₃₃^X = 122°, a₂₂^Z = 59°, and a₂₂^X = 66°. The anisotropy of the thermal expansion is due to specific features of the crystal structure of the compound.     

Synthesis and study of Np(V) and Pu(V) benzoate complexes with bipyridine

Heteroligand compounds AnO₂(bipy)OOCC₆H₅ (An = Np, Pu; bipy = α,α-bipyridine, C¹⁰H⁸N²) were synthesized and studied. It follows from powder X-ray patterns that these compounds are isostructural. Their unit cell parameters, determined by indexing of the powder X-ray patterns, are as follows: a = 9.2162 (7), b = 10.2339(8), c = 17.4083(17) Å, and β = 96.48(1)° for Np and a = 9.1983(18), b = 10.2052(18), c = 17.370(3) Å and β = 96.51(1)° for Pu. The compounds crystallize in the monoclinic system space group P2₁/n, Z = 4. The electronic absorption spectra of crystalline compounds suggest pentagonal-bipyramidal surrounding of the central atom and the prescence of cation-cation bonds with AnO ₂ ⁺ ions acting as monodentate ligands with respect to each other. The IR spectra of the compounds were recorded, and their thermal behavior in air was studied.     

Synthesis and structural characterization of CsNiP crystal

CsNiP crystals were synthesized by hydrothermal technique and characterized by the X-ray diffraction method. This alkaline transition metal phosphide crystallizes in the hexagonal system with space groupP6 ₃/mmc and cell parameters,a = 7.173(2) Å,c = 5.944(9) Å,V = 264.87(7) ų andZ = 2. The final residual factor isR1 = 0.0362 for 206 reflections withI > 2σ(I).     

Crystal and molecular structure of adducts of uranyl pivaloyltrifluoroacetonate with hexamethylphosphoramide and of uranyl trifluoroacetylacetonate with trimethyl phosphate

Crystal and molecular structures of adducts of uranyl pivaloyltrifluoroacetonate with hexamethylphosphoramide [UO₂(PTFA)₂(HMPA)] (I) and of uranyl trifluoroacetylacetonate with trimethyl phosphate [UO₂(TFA)₂(TMP)] (II) were determined. Compound I crystallizes in the monoclinic system, space group P2₁/n; a = 16.9384(3), b = 9.1090(2), c = 20.9844(4) Å, β = 101.5337(10)°, V = 3172.34(11) ų (at 100 K); Z = 4. Compound II crystallizes in the rhombic system, space group Pbca; a = 17.8214(4), b = 7.7786(2), c = 30.9176(7) Å, V = 4285.97(18) ų (at 100 K); Z = 8. In both cases, the cis isomer in which the neutral ligand is located between the trifluoromethyl groups is realized. Compound I differing from II by the stronger branching of ligand periphery is characterized by stronger structural deformations in the crystal.     

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.     

Crystal structures of Ln<Subscript>2</Subscript>TiO<Subscript>5</Subscript> (Ln = Gd,Dy) polymorphs

Single crystals of four Ln₂TiO₅ polymorphs have been grown, and their structures have been determined: orthorhombic (Gd₂TiO₅, a = 10.460(5), b = 11.317(6), c = 3.750(3) Å, Pnam, Z = 4), hexagonal (Gd_1.8Lu_0.2TiO₅, a = 3.663(3), c = 11.98(1) Å, P6₃/mmc, Z = 1.2), cubic (Dy₂TiO₅, a = 10.28(1) Å, Fd3m, Z = 10.4), and monoclinic (Dy₂TiO₅, a = 10.33(1), b = 3.653(5), c = 7.306(6) Å, β = 90.00(7)°, B2/m, Z = 2.4). The last polymorph has been identified for the first time.     

Phase relations and properties of alloys in the SnSe-DySe system

Phase relations in the SnSe-DySe system have been studied using differential thermal analysis, X-ray diffraction, microstructural analysis, microhardness tests, and density measurements, and its T-x phase diagram has been mapped out. The SnSe-DySe system contains a new ternary compound with the composition DySnSe₂, which crystallizes in orthorhombic symmetry with unit-cell parameters a = 5.74 ± 0.02 Å, b = 10.49 ± 0.03 Å, and c = 11.66 ± 0.05 Å (Z = 7, V = 702 ų, measured density ρ_meas = 7.02 g/cm³, X-ray density ρ_x = 7.26 g/cm³). In addition, the system contains SnSe-based solid solutions, Sn_{1 ? x} Dy _x Se (up to 4 mol % DySe). Their electrical conductivity and thermoelectric power have been measured as functions of temperature.     

Synthesis,characterization, theoretical investigation,and properties of monoclinic-phase InWO<Subscript>4</Subscript> hollow nanospheres

As a newly discovered member of the tungstate family, InWO₄ hollow nanospheres with a monoclinic wolframite structure were synthesized successfully. The crystal phase of InWO₄ was investigated via a combination of CASTEP geometric optimization and experimental simulation. InWO₄ has a space group of P2/c with two InWO₄ formula units per unit cell. The optimized cell dimensions are a = 5.16 Å, b = 5.97 Å, and c = 5.23 Å, with α = 90°, β = 92.11°, γ = 90°, giving a unit cell volume of 161.10 ų, which is consistent with the experimental measurements. More importantly, InWO₄ was a promising host material for different Ln³⁺ (Ln = Eu and Yb/Er) ions. For InWO₄:Yb³⁺/Er³⁺ excited at 980 nm, transitions from the ⁴G_11/2 (384 nm), ²H_9/2 (411 nm), and ⁴F_7/2 (487 nm) levels to the ground state (⁴I_15/2) of Er³⁺ were observed. In addition to the aforementioned properties, the InWO₄ hollow nanospheres can be used to improve the performance of dye-sensitized solar cells, which is chiefly attributed to theirlight scattering.

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X-ray analysis of 2-aniline benzo(2,3-<Emphasis Type="Italic">b</Emphasis>) cyclopentane-1,3-dione

The molecular and crystal structure of 2-aniline benzo(2,3-b) cyclopentane-1,3-dione has been determined by X-ray crystallographic techniques. This compound crystallizes in the orthorhombic space groupP2₁2₁2₁ with unit cell parameters:a = 5.467(1),b = 10.657(3),c = 19.602(6) Å;V = 1142.01(5) ų,Z = 4. The crystal structure has been resolved up to anR-factor 0.050 for 1129 reflections. All the three rings in the structure are planar. However, the dihedral angle between the phenyl ring and the moiety comprising of a five-membered and six-membered ring is 92.4°. The oxygen atom O1 acts as a trifurcated acceptor and is involved in the formation of three intermolecular interactions.     

Synthesis and properties of structural analogs of the mineral bournonite

Rare-earth analogs of the mineral bournonite, PbCuSbS₃, have been synthesized for the first time and their physicochemical properties have been studied. PbCuSbS₃, EuCuSbS₃, YbCuSbS₃, PbCuLaS₃, and PbCuNdS₃ are isostructural with each other and crystallize in orthorhombic symmetry with the following unit-cell parameters: a = 8.176, b = 8.660, c = 7.796 Å (PbCuSbS₃); a = 8.156, b = 8.68, c = 7.786 Å (EuCuSbS₃); a = 8.15, b = 8.64, c = 7.76 Å (YbCuSbS₃); a = 8.26, b = 8.84, c = 7.96 Å (PbCuLaS₃); a = 8.20, b = 8.80, c = 7.92 Å (PbCuNdS₃) (Z = 4, sp. gr. Pmn2₁).     

X-ray structure determination and analysis of hydrogen interactions in 3, 3′-dimethoxybiphenyl

The crystal structure of 3, 3′-dimethoxybiphenyl has been determined by X-ray diffraction methods with an aim of describing the hydrogen interaction in biphenyl derivatives. The title compound crystallizes in monoclinic space groupP2₁/c with unit cell dimensions,a = 7.706(1),b = 11.745(2),c = 12.721(2) Å, β = 92.31(1)°,Z = 4 and its structure has been refined up to the reliability index of 3.8%. The average torsion angle about the inter-ring C-C bond is 37.5°. The O1 and Ol′ atoms of the methoxy group are deviated by 0.046(1) Å and 0.234(1) Å from the mean planes of respective rings. The crystal cohesion is pronounced due to three-inter-molecular C-H...O hydrogen bonds.     

Crystal and molecular structure of [TcCl(CO)<Subscript>5</Subscript>] and [TcBr(CO)<Subscript>5</Subscript>]. Correlations with the reactivity and electronic structure

The crystal and molecular structures of [TcCl(CO)₅] and [TcBr(CO)₅] were determined. The compounds crystallize in the rhombic system, space group Pnma; a = 11.6757(18) and 11.9564(18) Å, b = 11.7365(14) and 11.7250(18) Å, c = 6.0407(7) and 6.2020(15) Å, V = 827.77(19) and 869.5(3) ų, respectively; Z = 4. The structural data for pentacarbonyl halides were compared in the series Mn-Tc-Re and Cl-Br-I. Quantum-chemical calculations of the compounds [TcX(CO)₅] (X = F, Cl, Br, I) and of the anion [TcCl₃(CO)₃]^2? were made. A correlation between the geometry, electronic structure, and reactivity of the complexes is considered.     

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.     

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.     

Crystal growth and physicochemical properties of structural analogs of krupkaite

Single crystals of rare-earth analogs of the mineral krupkaite, CuPbBi₃S₆, have been prepared for the first time, and their physicochemical properties have been studied. The compounds CuYbBi₃S₆, CuEuEr₃S₆, CuYbEr₃S₆, and CuPbEr₃S₆ are isostructural with CuPbBi₃S₆ and crystallize in orthorhombic symmetry (sp. gr. Pb2₁ m, Z = 2): a = 11.204, b = 11.376, c = 3.960 Å (CuYbBi₃S₆); a = 11.244, b = 11.440, c = 3.998 Å (CuEuEr₃S₆); a = 11.30, b = 11.55, c = 4.03 Å (CuPbEr₃S₆); a = 11.236, b = 11.414, c = 3.98 Å (CuYbEr₃S₆).     

Synthesis and structure of the CsSmP<Subscript>4</Subscript>O<Subscript>12</Subscript> cyclotetraphosphate (cubic CsNdP<Subscript>4</Subscript>O<Subscript>12</Subscript> structure)

CsSmP₄O₁₂ crystals have been prepared at 300°C in molten polyphosphoric acids containing Cs, Mg, and Sm cations, and their crystal structure has been determined: sp. gr. I \(\bar 4\) 3d, a = 15.1225(8) Å, Z = 12, CsNdP₄O₁₂ structure.     

Crystal and molecular structure of uranyl acetylacetonate dimer, [UO<Subscript>2</Subscript>(C<Subscript>5</Subscript>H<Subscript>7</Subscript>O<Subscript>2</Subscript>)<Subscript>2</Subscript>]<Subscript>2</Subscript>

The crystal and molecular structure of uranyl acetylacetonate dimer was determined by single crystal X-ray diffraction. The compound crystallizes in the tetragonal system, a = 7.9420(2), c = 40.1240(13) Å (at 100 K), Z = 4, space group P4₁2₁2. Dimeric uranyl acetylacetonate molecules in the crystal are formed by bridging bonding of one of O atoms of the acetylacetonate ligands with U atoms, so that the coordination polyhedra of U atoms (distorted pentagonal bipyramids) share a common equatorial edge. The dimer has a nonplanar structure, being significantly bent along the conventional line connecting the bridging O atoms.     

Synthesis and crystal structure of [UO<Subscript>2</Subscript>(OH)(CO(NH<Subscript>2</Subscript>)<Subscript>2</Subscript>)<Subscript>3</Subscript>]<Subscript>2</Subscript>(ClO<Subscript>4</Subscript>)<Subscript>2</Subscript>

The complex [UO₂(OH)(CO(NH₂)₂)₃]₂(ClO₄)₂ (I) was synthesized. A single crystal X-ray diffraction study showed that compound I crystallizes in the triclinic system with the unit cell parameters a = 7.1410(2), b = 10.1097(2), c = 11.0240(4) Å, α = 104.648(1)°, β = 103.088(1)°, γ = 108.549(1)°, space group \(P\bar 1\), Z = 1, R = 0.0193. The uranium-containing structural units of the crystals are binuclear groups [UO₂(OH)· (CO(NH₂)₂)₃] ₂ ²⁺ belonging to crystal-chemical group AM²M ₃ ¹ [A = UO ₂ ²⁺ , M² = OH^?, M¹ = CO(NH₂)₂] of uranyl complexes. The crystal-chemical analysis of nonvalent interactions using the method of molecular Voronoi-Dirichlet polyhedra was performed, and the IR spectra of crystals of I were analyzed.