Crystal and molecular structure of phenanthrolinium peroxodisulfate dihydrate (C<Subscript>12</Subscript>H<Subscript>9</Subscript>N<Subscript>2</Subscript>)<Subscript>2</Subscript>S<Subscript>2</Subscript>O<Subscript>8</Subscript> · 2H<Subscript>2</Subscript>O

The crystal structure of (HPhen)₂S₂O₈ · 2H₂O is studied using X-ray diffraction. The crystals are monoclinic, a = 23.716(5) Å, b = 10.220(2) Å, c = 13.103(3) Å, β = 128.03(2)°, V = 2501.6(9) ų, Z = 4, space group C2/c, and R = 0.0745 for 1579 reflections with I > 2σ(I). The crystal is built of S₂O ₈ ^2? centrosymmetric anions, HPhen ⁺ cations, and molecules of crystallization water. Hydrogen bonds link the structural units into chains. Within a chain, stacking interactions are observed between the phenanthroline rings (the interplanar spacing between the rings is 3.8 Å, and the dihedral angle between their planes is 8°). The data of IR spectroscopy confirm the formation of the N(Phen)-H bond.     

Crystal structure of the solid solution NH<Subscript>4</Subscript>Al<Subscript>0.62</Subscript>Cr<Subscript>0.38</Subscript>(SO<Subscript>4</Subscript>)<Subscript>2</Subscript> · 12H<Subscript>2</Subscript>O

The solid solution NH₄Al_0.62Cr_0.38(SO₄)₂ · 12H₂O was studied by X-ray diffraction. The crystal structure was determined in a series of the maximal subgroups Pa3? > R3? > P1? > P1. Reflections forbidden in sp. gr. Pa3? are indicative of symmetry lower than cubic. In the centrosymmetric models under consideration, all sulfate groups are oppositely oriented with respect to each other. In non-centrosymmetric sp. gr. P1, four of the eight sulfate groups have the same orientation, whereas the other four groups are oriented in an opposite direction.     

Synthesis and structure of [(NH<Subscript>2</Subscript>)<Subscript>2</Subscript>CSSC(NH<Subscript>2</Subscript>)<Subscript>2</Subscript>]<Subscript>2</Subscript>[OsBr<Subscript>6</Subscript>]Br<Subscript>2</Subscript> · 3H<Subscript>2</Subscript>O

The complex [(NH₂)₂CSSC(NH₂)₂]₂[OsBr₆]Br₂ · 3H₂O is synthesized by the reaction of K₂OsBr₆ with thiocarbamide in concentrated HBr and characterized using electronic absorption and IR absorption spectroscopy. Its crystal structure is determined by X-ray diffraction. The crystals are orthorhombic, a = 11.730(2) Å, b = 14.052(3) Å, c = 16.994(3) Å, space group Cmcm, and Z = 4. The [OsBr₆]^2? anionic complex has an octahedral structure. The Os-Br distances fall in the range 2.483–2.490 Å. The α,α′-dithiobisformamidinium cation is a product of the oxidation of thiocarbamide. The S-S and C-S distances are 2.016 and 1.784 Å, respectively. The H₂O molecules, Br^?ions, and NH₂ groups of the cation are linked by hydrogen bonds.     

Non-isothermal crystallization kinetics of Fe<Subscript>2</Subscript>O<Subscript>3</Subscript>–CaO–SiO<Subscript>2</Subscript> glass containing nucleation agent P<Subscript>2</Subscript>O<Subscript>5</Subscript>/TiO<Subscript>2</Subscript>

Fe₂O₃–CaO–SiO₂ glass ceramics containing nucleation agent P₂O₅/TiO₂ were prepared by sol-gel method. The samples were characterized by X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The activation energy and kinetic parameters for crystallization of the samples were calculated by the Johnson-Mehi-Avrami (JMA) model and Augis-Bennett method according to the results of DSC. The results showed that the crystallization mechanism of Fe₂O₃–CaO–SiO₂ glass, whose non-isothermal kinetic parameter n = 2.3, was consistent with surface crystallization of the JMA model. The kinetics model function of Fe₂O₃–CaO–SiO₂ glass, f(α) = 2.3(1–α)[–ln(1–α)]^0.57, was also obtained. The addition of nucleation agent P₂O₅/TiO₂ could reduce the activation energy, which made the crystal growth modes change from onedimensional to three-dimensional.     

Crystal structure and properties of K<Subscript>2</Subscript>[OsO<Subscript>2</Subscript>(C<Subscript>2</Subscript>O<Subscript>4</Subscript>)<Subscript>2</Subscript>] · 2H<Subscript>2</Subscript>O

The synthesis and X-ray diffraction study of the compound K₂[OsO₂(C₂O₄)₂] · 2H₂O are performed. The compound crystallizes in the triclinic crystal system, space group P \(\bar 1\), a = 6.545(1) Å, b = 6.835(2) Å, c = 7.595(2) Å, α = 85.76(2)°, β = 65.33(2)°, γ = 71.14(2)°, and Z = 1. The osmium atom is located at the center of symmetry and has a distorted octahedral coordination formed by oxygen atoms: two oxygen atoms of the osmyl group occupy the apical positions [Os-O, 1.730(2) Å], and four oxygen atoms of the oxalate ions lie in the equatorial plane. The K⁺ cation is surrounded by ten oxygen atoms located at different K-O distances in the range from 2.787(2) to 3.158(2) Å. The assignment of the absorption bands in the IR spectrum of K₂[OsO₂(C₂O₄)₂] · 2H₂O is performed. The electronic absorption spectra of the compound are recorded in different solvents, and the thermal behavior in air is studied.     

Synthesis and X-ray diffraction study of [UO<Subscript>2</Subscript>(NO<Subscript>3</Subscript>)<Subscript>2</Subscript>(H<Subscript>2</Subscript>O)<Subscript>2</Subscript>] · 2C<Subscript>12</Subscript>H<Subscript>18</Subscript>O

The compound [UO₂(NO₃)₂(H₂O)₂] · 2C₁₂H₁₈O was synthesized and studied by IR spectroscopy and X-ray diffraction. The structure consists of the neutral island groups [UO₂(NO₃)₂(H₂O)₂], which belong to the crystal-chemical group AB ⁰¹ ₂ M ¹ ₂ (A = UO₂ ²⁺, B ⁰¹ = NO₃⁻, M ¹ = H₂O) of uranyl complexes, and 1-adamantyl methyl ketone molecules. The characteristic features of the association of the complexes [UO₂(NO₃)₂(H₂O)₂] and 1-adamantyl methyl ketone molecules in the crystal structure via hydrogen bonds are considered with the use of Voronoi-Dirichlet polyhedra.     

Synthesis and crystal structure of Na<Subscript>3</Subscript>(H<Subscript>3</Subscript>O)[UO<Subscript>2</Subscript>(SeO<Subscript>3</Subscript>)<Subscript>2</Subscript>]<Subscript>2</Subscript>· H<Subscript>2</Subscript>O

Single crystals of the compound Na₃(H₃O)[UO₂(SeO₃)₂]₂ · H₂O (I) have been synthesized, and their structure has been investigated using X-ray diffraction. Compound I crystallizes in the triclinic system with the unit cell parameters a = 9.543(6)Å, b = 9.602(7)Å, c = 11.742(8)Å, α = 66.693(16)°, β = 84.10(2)°, γ = 63.686(14)°, space group P \(\bar 1\), Z = 2, and R = 0.0734. The uranium-containing structural units of the crystals are [UO₂(SeO₃)₂]^2? chains, which belong to the crystal-chemical group AB ² B ¹¹ (A = UO ₂ ²⁺ , B ² = SeO ₃ ^2? , B ¹¹ = SeO ₃ ^2? ) of the uranyl complexes. The structures of the compounds containing the [UO₂(SeO₃)₂]^2? anionic complexes are compared.     

X-ray diffraction study of Rb<Subscript>2</Subscript>[(UO<Subscript>2</Subscript>)<Subscript>2</Subscript>(CrO<Subscript>4</Subscript>)<Subscript>3</Subscript>(H<Subscript>2</Subscript>O)<Subscript>2</Subscript>] · 4H<Subscript>2</Subscript>O

The compound Rb₂[(UO₂)₂(CrO₄)₃(H₂O)₂] · 4H₂O was studied by X-ray diffraction. The crystals are monoclinic, a = 10.695(2) Å, b = 14.684(3) Å, c = 14.125(3) Å, β = 108.396(4)°, sp. gr. P2₁/c, Z = 4, V = 2104.9(7) ų, and R = 0.0491. The main structural units are layers consisting of [(UO₂)₂(CrO₄)₃(H₂O)₂]^2? anions belonging to the crystal-chemical group A ₂ T ₂ ³ B ²M ₂ ¹ (A = UL ₂ ²⁺ , T ³ and B ² are CrO ₄ ^2? , and M ¹ is H₂O) of uranyl complexes. The uranium-containing layered groups are held together by electrostatic interactions with rubidium cations, as well as by hydrogen bonds with the participation of inner- and outer-sphere water molecules.     

New crystals of the CsHSO<Subscript>4</Subscript>–CsH<Subscript>2</Subscript>PO<Subscript>4</Subscript>–H<Subscript>2</Subscript>O system

Cs₆H(HSO₄)₃(H₂PO₄)₄ crystals, grown for the first time based on an analysis of the phase diagram of the CsHSO₄–CsH₂PO₄–H₂O ternary system, have been investigated by structural analysis using synchrotron radiation. The atomic structure of the crystals is determined and its specific features are analyzed.     

Crystal structure of the cubic β<Subscript>ms</Subscript>-phase of a La<Subscript>1.82</Subscript>Bi<Subscript>0.18</Subscript>Mo<Subscript>2</Subscript>O<Subscript>9</Subscript> single crystal at 33 K

Single crystals of the cubic β_ms-phase of La_1.82Bi_0.18Mo₂O₉ have been characterized for the first time by precision X-ray diffraction at 33 K. The structure of a crystal determined at T = 33 K is identical to the structure studied at room temperature. It is confirmed that the La, Mo1, and O1 atoms deviate from their positions on the threefold axis in the high-temperature β-phase; part of lanthanum atoms is substituted by bismuth atoms, which are located on the threefold axis; part of the molybdenum atoms return to the position on the threefold axis.     

Synthesis and crystal structure of [UO<Subscript>2</Subscript>CrO<Subscript>4</Subscript>(C<Subscript>5</Subscript>NH<Subscript>5</Subscript>COO)<Subscript>2</Subscript>(H<Subscript>2</Subscript>O)]·2H<Subscript>2</Subscript>O

Crystals of UO₂CrO₄(C₅NH₅COO)₂(H₂O)] · 2H₂O are synthesized and their structure is studied by X-ray diffraction. The compound crystallizes in the triclinic crystal system. The unit cell parameters are as follows: a = 7.0834(10) Å, b = 10.6358(14) Å, c = 12.9539(17) Å, α = 75.096(2)°, β = 74.490(2)°, and γ = 80.657(2)°; V = 904.1(2) ų, space group P \(\bar 1\), Z = 2, and R = 0.026. The structure is built of [UO₂CrO₄(C₅NH₅COO)₂(H₂O)]₂ centrosymmetric dimers, which are linked into a framework by a system of hydrogen bonds involving inner-sphere and outer-sphere water molecules. The coordination number of the U(VI) atom is seven, and the coordination polyhedron is a pentagonal bipyramid with the oxygen atoms of the uranyl group, two chromate groups, two molecules of isonicotinic acid, and a water molecule at the vertices. The crystal chemical formula of the [UO₂CrO₄(C₅NH₅COO)₂(H₂O)]₂ dimer is represented as AB ² M ₃ ¹ , where AB ² M ₃ ¹ , where A = UO ₂ ²⁺ , B ² = CrO ₄ ^2? , and M ¹ = = C₅NH₄COOH and H₂O.     

Na<Subscript>3</Subscript>Tb<Subscript>3</Subscript>[Si<Subscript>6</Subscript>O<Subscript>18</Subscript>] · H<Subscript>2</Subscript>O,a synthetic analogue of microporous mineral gerenite

Crystals of a new silicate, Na₃Tb₃[Si₆O₁₈] · H₂O, space group \(P\bar 1\), are obtained under hydrothermal conditions. The formula of the compound is determined in the course of structure solution. The silicate is a synthetic analogue of the gerenite mineral (Ca_1.21Na_0.57)(Y_2.24Dy_0.68)Si₆O₁₈ · 2H₂O, whose structure contains six-membered rings formed by SiO₄ tetrahedra. The [Si₆O₁₈] rings are connected by TbO₆ octahedra into a mixed microporous framework with voids filled by Na atoms and water molecules. The new silicate differs from gerenite by the occupation of the Ca position by Na atoms and population of the pores sandwiched between six-membered rings. By virtue of conditions of hydrothermal synthesis in the absence of Ca and excess of Na in the system, an additional Na position appears in the void. It is populated statistically, and in gerenite it was occupied by water molecules only. In the new structure, the position of water is split into two statistically populated positions. The inclusion of Na atoms in additional positions in framework pores and their high thermal vibrations are indicative of ion-exchange properties of the structure. Possible paths of ion exchange are discussed.     

Crystal structure and properties of [OsO<Subscript>2</Subscript>(NH<Subscript>3</Subscript>)<Subscript>4</Subscript>]SO<Subscript>4</Subscript> · H<Subscript>2</Subscript>O

The structure of a single crystal of tetraammindioxoosmium(VI) sulfate [OsO₂(NH₃)₄]SO₄ · H₂O, which is synthesized by the reaction of K₂[OsO₂(OH)₄] with (NH₄)₂SO₄ in an aqueous solution, is investigated using X-ray diffraction analysis. The compound crystallizes in the monoclinic crystal system, space group P2₁/c, a = 13.102(2) Å, b = 6.158(3) Å, c = 11.866(2) Å, β = 98.13(2)°, and Z = 4. The [OsO₂(NH₃)₄]SO₄ · H₂O compound has an island structure. Two crystallographically independent osmium atoms are situated at the centers of symmetry, and their octahedral coordination includes two oxygen atoms and four nitrogen atoms of the ammonia molecules. In both octahedra, the osmyl group is linear. The Os-O distances in the octahedra are identical within the standard deviations [Os(1)-O, 1.762(2) Å; Os(2)-O, 1.769(2) Å]. The Os-N bond lengths vary from 2.082(3) to 2.101(3) Å. The cationic complexes, SO₄ groups, and water molecules are linked via the system of hydrogen bonds. The assignment of the absorption bands in the IR spectrum of the compound synthesized is performed, and its thermal behavior in air is studied.     

Crystal structure of byelorussite-(Ce) NaMnBa<Subscript>2</Subscript>Ce<Subscript>2</Subscript>(TiO)<Subscript>2</Subscript>[Si<Subscript>4</Subscript>O<Subscript>12</Subscript>]<Subscript>2</Subscript>(F,OH) · H<Subscript>2</Subscript>O

The crystal structure of the mineral byelorussite-(Ce) NaMnBa₂Ce₂Ti₂Si₈O₂₆(F,OH) · H₂O belonging to the joaquinite group was solved and refined to R = 0.033 based on 4813 reflections with I > σ2(I). The parameters of the orthorhombic unit cell are a = 22.301(4) Å, b = 10.514(2) Å, c = 9.669(2) Å, V = 2267.1(8) ų, sp. gr. Ama2, and Z = 4. The structure is composed of three-layer sheets, which consist of dimers of edge-sharing Ti octahedra located between isolated four-membered [Si₄O₂] rings. The sheets are linked to each other by Mn 5-vertex polyhedra to form a heteropolyhedral framework. Large cavities in the framework are occupied by Na 6-vertex polyhedra, Ba 11-vertex polyhedra, and REE 9-vertex polyhedra.     

Ga<Subscript>2</Subscript>O<Subscript>3</Subscript>–In<Subscript>2</Subscript>O<Subscript>3</Subscript> thin films on sapphire substrates: Synthesis and ultraviolet photoconductivity

The structure and electrical and optical properties of β-Ga₂O₃–In₂O₃ thin films on sapphire substrates with different orientations have been investigated. The samples have been prepared by annealing of gallium–indium metallic films on sapphire substrates in air at different gallium-to-indium ratios in the initial mixture. The photoconductivity of these structures in the solar-blind ultraviolet spectral region has been examined.     

X-ray diffraction study of Ba<Subscript>3</Subscript>TaFe<Subscript>3</Subscript>Si<Subscript>2</Subscript>O<Subscript>14</Subscript> single crystal—a promising langasite-type multiferroic

Ba₃TaFe₃Si₂O₁₄ single crystals (sp. gr. P321, Z = 1), promising langasite-type multiferroics, have been grown by floating zone melting. An accurate X-ray diffraction study of Ba₃TaFe₃Si₂O₁₄ single crystal has been performed using two datasets, obtained independently for two different orientations of the same sample on a diffractometer equipped with a CCD area detector at 295 K. Structure refinement is performed based on an averaged dataset: a = 8.5355(1) Å, c = 5.2332(1) Å, sp. gr. P321, Z = 1; the R factors of model structure refinement were found to be R/wR = 1.02/1.23% for 4552 independent reflections. Disordering asymmetry is revealed for the magnetic Fe ion in the 3f site and the Ba cation in the 3e site.     

Synthesis and Crystal Structure of Ethylenediammonium bis iodate tetra iodic Acid: [C<Subscript>2</Subscript>H<Subscript>10</Subscript>N<Subscript>2</Subscript>] (IO<Subscript>3</Subscript>)<Subscript>2</Subscript>·4HIO<Subscript>3</Subscript>

Abstract  

The synthesis and crystal structure are presented for the ethylenediammonium bis iodate tetra iodic acid. An X-ray investigation has shown that this compound crystallizes in a centrosymmetric monoclinic system, space group P2₁/c with the lattice parameters: a = 7.2536(2) ?, b = 18.5351(5) ?, c = 7.5685(2) ?, β = 107.937(1)°, V = 968.10(3) ?³. The structure was solved from 5281 independent reflections with R ₁ = 0.0229 and wR ₂ = 0.0428, and refined with 156 parameters. The structure is built up of [(CH₂)₂(NH₃)₂]²⁺ cations connected to the one-dimensional [HIO₃]_n chains and to the [H₂I₄O₁₂]²⁻ clusters by a weak N–H···O hydrogen bonds.     

Structural investigation of anion-deficient manganites La<Subscript>0.7</Subscript>Sr<Subscript>0.3</Subscript>MnO<Subscript>3 − δ</Subscript>

The crystal structure of the anion-deficient manganites La_0.7Sr_0.3MnO_{3 ? δ} (δ = 0, 0.10, 0.15, 0.20) is investigated using high-resolution neutron diffraction. At room temperature, the crystal structure of the stoichiometric manganite La_0.7Sr_0.3MnO₃ and the anion-deficient manganite La_0.7Sr_0.3MnO_2.9 is satisfactorily described in rhombohedral space group R \(\bar 3\) c. The anion-deficient manganite La_0.7Sr_0.3MnO_2.85 is characterized by two perovskite phases with space groups R \(\bar 3\) c and 14/mcm. The crystal structure of the La_0.7Sr_0.3MnO_2.8 manganite corresponds to the structure of a perovskite phase with space group I4/mcm. It is established that the phase separation in the crystal structure of the La_0.7Sr_0.3MnO_{3 ? δ} manganites at a temperature of 293 K is associated with a nonuniform distribution of oxygen vacancies.     

Synthesis and crystal structure of binuclear molecule Ho<Subscript>2</Subscript>(2-FC<Subscript>6</Subscript>H<Subscript>4</Subscript>COO)<Subscript>6</Subscript>⋅4H<Subscript>2</Subscript>O

The complex Ho₂(2-FC₆H₄COO)₆?4H₂O has been synthesized and structurally characterized by single crystal X-ray diffraction methods. The complex crystallizes in the triclinic system with space group P \(\bar 1\), lattice parameters a = 9.293(8) Å, b = 9.845(8) Å, c = 12.703(11) Å, α = 85.470(14)^°, β = 87.537(12)^°, γ = 62.485(11)^°, V = 1027.5(15) ų, Z = 1, D_calc = 1.998 Mg/m³. The Ho³⁺ ion is in distorted monocapped square-antiprism coordination environment and is coordinated by nine oxygen atoms, seven from five 2-FC₆H₄COO^2? groups, two from two water molecules. Two Ho³⁺ ions are linked together by four bridging carboxylate groups to form a binuclear molecule with inversion center.     

New Diphosphopentamolybdate K<Subscript>5</Subscript>[HP<Subscript>2</Subscript>Mo<Subscript>5</Subscript>O<Subscript>23</Subscript>] · 10H<Subscript>2</Subscript>O: Synthesis,Structure, and Characterization

A new diphosphopentamolybdate(VI) K₅[HP₂Mo₅O₂₃] · 10H₂O has been prepared employing solution method and characterized by single crystal X-ray diffraction, energy dispersive analysis, infrared spectroscopy, thermal stability analysis, cyclic voltammetry analysis, and ultraviolet visible spectroscopy. The compound crystallizes in the orthorhombic sp. gr. Pcab: a = 15.9661(10) Å, b = 19.0832(10) Å, c = 20.0970(9) Å, V = 6123.27(10) Å3, Z = 8. The crystal structure contains the polyanion units [HP₂Mo₅O₂₃]^5– around the potassium cations and lattice water. The [HP₂Mo₅O₂₃]^5– subunits are connected together through K?O?Mo bridges and hydrogen bonds. The crystal shape morphology was simulated using the Bravais–Friedel–Donnay–Harker model.