Crystal structure of the molecular adduct of antimony(III) fluoride with L-phenylalanine

The crystal structure of a newly synthesized molecular adduct of antimony(III) fluoride with L-phenylalanine of the composition SbF₃(C₉H₁₁NO₂) is determined for the first time (monoclinic crystal system: a = 5.8742(1) ?, b = 6.2079(1) ?, c = 15.5401(3) ?, β = 90.741(1)°, Z = 2, P2₁ space group). The structure consists of SbF₃ molecules and L-phenylalanine bound into polymer chains by bidentate bridging carboxyl groups of amino acid molecules. Weak Sb⋯F(3)^b bonds organize the adjacent chains into polymer ribbons that are bound into layers by N-H⋯F and N-H⋯O hydrogen bonds.     

Scattering of very cold neutrons from the supramolecular structure of ethylene copolymers with substituted norbornene, 5-ethylidene-2-norbornene

The transformation of the nanostructure of ethylene copolymers with 5-ethylidene-2-nonbornene due to variations in the concentration of 5-ethylidene-2-nonbornene is studied using scattering of very cold neutrons. The cyclic monomer is introduced into the polyethylene chain in order to modify the supramolecular structure of polyethylene and to change its macroscopic properties. It is shown that, as the content of 5-ethylidene-2-nonbornene in the copolymer increases, the amorphous-crystalline structure of polyethylene is destroyed (the crystallinity and average crystallite size decrease). Neither scattering of very cold neutrons nor X-ray diffraction are observed in samples of ethylene copolymers in which the content of 5-ethylidene-2-nonbornene exceeds 35 mol %. The transmission of light in copolymers of ethylene with 5-ethylidene-2-nonbornene is measured at different wavelengths. It is found that an increase in the content of 5-ethylidene-2-nonbornene in the copolymer leads to an increase in the transparency of the material.     

ChemInform Abstract: Structural Transformation Between Two Cubic Phases of (NH4)3SnF7.

Single crystals of (NH₄)₃SnF₇ are obtained from aqueous solutions of (NH₄)₂SnF₆ and excess NH₄F during solvent evaporation.     

Crystal Structure of <Emphasis Type="Italic">DL</Emphasis>-Valinium Tetrafluoroantimonate(III) Monohydrate

The crystal structure of an antimony(III) fluoride complex of the composition (C₅H₁₂NO₂)SbF₄·H₂O (I) involving a cation of α-amino isovaleric acid (DL-valine, Val) is determined. Crystals are monoclinic: a = 12.2024(2) Å, b = 6.1636(1) Å, c = 15.5167(3) Å, Z = 4, space group P2₁/c. The structure is formed of DL-valinium (C₅H₁₂NO₂)⁺ cations, complex [SbF₄]_n^n? anions having a polymeric chain structure, and crystallization water molecules. The [SbF₄]_n^n? complex anions consist of trigonal SbF4E bipyramids joined together by asymmetric bridging Sb–F(3)···Sb bonds. The structural units are organized into a threedimensional framework via N–H···F, N–H···O, and O–H···F hydrogen bonds.     

Sb(III) fluoride complexes with DL-valine. Crystal structure of molecular complex SbF<Subscript>3</Subscript>{(CH<Subscript>3</Subscript>)<Subscript>2</Subscript>CHCH(<Superscript>+</Superscript>NH<Subscript>3</Subscript>)COO<Superscript>−</Superscript>}

Preparative method in combination with X-ray diffraction and IR spectroscopy is used to study reaction of Sb(III) fluoride with -aminoisovaleric acid (DL-valine) in an aqueous solution in the range of the molar ratios of components (0.25–2) : 1 in the presence of hydrofluoric acid. The molecular complex of Sb(III) fluoride with valine (1 : 1) of the composition SbF₃{(CH₃)₂CHCH(⁺NH₃)COO^–}(I) and valinium tetrafluoro-antimonate(III) monohydrate {(CH₃)₂CHCH(₊NH₃)COOH}SbF₄· H₂O (II) are synthesized for the first time. Crystal structure was determined for the molecular complex I consisting of SbF₃ groups and valine molecules united into polymer chains through bidentate bridging carboxylate groups of amino acid molecules.Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 2, 2005, pp. 125–131.Original Russian Text Copyright © 2005 by Zemnukhova, Davidovich, Udovenko, Kovaleva.     

Crystal structure of monohydrate and anhydrous β-alaninium tetrafluoroantimonates(III)

Novel complexes of Sb(III) fluorides with cation of -aminopropionic acid (-alanine), (NH₃(CH₂)₂COOH)SbF₄ H₂O (I) and (NH₃(CH₂)₂COOH)SbF₄ (II), are synthesized and their crystal structures are determined. Crystals I and II are monoclinic with a = 12.1580(5) , b = 7.4167(4) , c = 10.1540(5) , = 108.222(2)°, Z = 4, space group P2₁/c for (I) and a = 10.483(1) , b = 7.5906(8) , c = 9.4237(9) , = 90.548(2)°, Z = 4, space group P2₁/c for (II). Structures I and II are formed by -alaninium cations (C₃H₈NO₂)⁺ and complex anions [SbF₄] _n ^n– with polymer chain structure. Complex I also contains crystallization water molecules. In the structures of complexes I and II, the -alaninium cations have different conformation, the torsion angles C(1)C(2)C(3)N in these complexes are 174.5° and 77.0°C, respectively.__________Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 4, 2005, pp. 243–247.Original Russian Text Copyright © 2005 by Udovenko, Zemnukhova, Kovaleva, Davidovich.     

The Structure and Vibrational Spectra of Gallium(III) Fluoride Dimeric Complex with Tetramethylammonium Cation

Optics and Spectroscopy - We have determined the crystal structure of gallium(III) fluoride dimeric complex [N(CH3)4]2[Ga2F8(H2O)2], which is composed of [N(CH3)4]+ tetrahedral cations and...     

Structural investigation of cooperite (PtS) crystals

The single-crystal structure of cooperite, a natural platinum sulfide PtS, is studied by X-ray diffraction supported by high-resolution scanning transmission electron microscopy and X-ray spectrum microanalysis. It is found that, in addition to the main reflections corresponding to the known tetragonal cell (a = 3.47 and c = 6.11 Å; space group P4₂/mmc), many weak reflections with intensities I ≤ 60σ(I) are clearly observed. These reflections fit the tetragonal cell (space group I4/mmm) with doubled parameters. In structures with small (P4₂/mmc) and large (I4/mmm) cells, the S atoms occupy statistically two special positions. It is shown that the chemical composition of the cooperite crystals deviates from the stoichiometric composition: sulfur-deficient specimens predominate.