Crystal structure and spectroscopic properties of AVO2SO4 (A = K, Rb) compounds

The crystal structure of alkali-metal dioxovanadium(V) sulfates AVO₂SO₄, where A is K or Rb, has been determined based on a combination of neutron and X-ray diffraction data. The compounds are isostructural and have an orthorhombic lattice (space group P2₁2₁2₁, Z = 4) with unit cell parameters a = 11.1004(2) and 10.8193(1) Å; b = 8.2626(2) and 8.9042(1) Å; c = 5.4772(1) and 5.5722(1) Å, respectively. The structures are of the chain type. Zigzag chains are formed by vertex-sharing VO₆ octahedra. Sulfate groups SO₄ link neighboring chains and form a spatial framework with cavities accommodating alkali-metal atoms with CN = 9 (K) and 8 (Rb). IR and Raman spectroscopy data are reported.     

Crystal structure of RbNbO(SO4)2

Journal of Structural Chemistry -     

Crystal structure and spectroscopic properties of Na(2)K(6)(VO)(2)(SO(4))(7)

Red-brown crystals of a new mixed alkali oxo sulfato vanadium(V) compound Na(2)K(6)(VO)(2)(SO(4))(7), suitable for X-ray determination, have been obtained from the catalytically important binary molten salt system M(2)S(2)O(7)-V(2)O(5) (M = 80% K and 20% Na). By slow cooling of a mixture with the mole fraction X(V(2)O(5)) = 0.24 from 325 degrees C, i.e., just below the liquidus temperature, to the solidus temperature of around 300 degrees C, a dark reddish amorphous phase was obtained containing crystals of the earlier described V(V)-V(IV) mixed valence compound K(6)(VO)(4)(SO(4))(8) and Na(2)K(6)(VO)(2)(SO(4))(7) described here. This compound crystallizes in the tetragonal space group P4(3)2(1)2 (No. 96) with a = 9.540(3) A, c = 29.551(5) A at 20 degrees C and Z = 4. It contains a distorted VO(6) octahedron with a short V-O bond of 1.552(6) A, a long one of 2.276(5) A trans to this, and four equatorial V-O bonds in the range 1.881(6)-1.960(6) A. The deformation of the VO(6) octahedron is less pronounced compared to that of the known oxo sulfato V(V) compounds. Each VO(3+) group is coordinated to five sulfate groups of which two are unidentately coordinated and three are bidentate bridging to neighboring VO(3+) groups. The length of the S-O bonds in the S-O-V bridges of the two unidentately coordinated sulfato groups are 1.551(6) A and 1.568(6) A, respectively, which are unusually long compared to our earlier measurements of sulfate groups in other V(III), V(IV), and V(V) compounds.     

Crystal structure and spectroscopic characterization of K8(VO)2O(SO4)6

Red and yellow dichroistic crystals of a vanadium(V) compound, potassium (mu-oxo, di-mu-sulfato)bis(oxodisulfatovanadate), K(8)(VO)(2)O(SO(4))(6), have been obtained from the ternary catalytic model melt system K(2)S(2)O(7)[bond]K(2)SO(4)[bond]V(2)O(5). By slow cooling of the melt from 420 to 355 degrees C, crystal growth occurred, using solid V(2)O(5) crystals present in the melt as nucleation promoter. The compound crystallizes in the monoclinic space group P2(l) with a = 13.60(9) A, b = 13.93(9) A, c = 14.05(9) A, beta = 90.286(10) degrees, and Z = 2. It contains two VO(6) octahedra linked together by a mu-oxo and two mu-sulfato bridges. Furthermore, each octahedron has two monodentate sulfate ligands, making the dimeric entity coordinatively saturated. IR spectroscopy shows bands arising from V[bond]O[bond]V and V[double bond]O stretches as well as splitting of sulfate bands due to the different degrees of freedom present for different conformations of sulfate ligands. The coordination of vanadium in K(8)(VO)(2)O(SO(4))(6) is discussed in relation to the reaction mechanism of SO(2) oxidation catalysis.     

Crystal structure and spectroscopic properties of ammonium hydrogensquarate squaric acid monohydrate

The structure of ammonium hydrogensquarate squaric acid monohydrate has been determined by single crystal X-ray diffraction. The compound crystallizes in the monoclinic space group C2/c and exhibits a 3D network with molecules linked by intermolecular interactions with participation of the H₂Sq, HSq^?, NH₄ ⁺, and H₂O species. The HSq^? anion and the neutral H₂Sq form a strong head-to-tail dimer through O–H···O hydrogen bonding with lengths of 2.587 and 2.494 Å (protected space between numeral and unit). The layers are connected by ammonium cations and water molecules in a plane through the O···N (2.950, 2.978, 3.036 Å) and O···O (2.953, 2.781 Å) bonds. Another such layer is connected to the NH₄ ⁺ cation in the adjacent plane through bifurcated N–H···O hydrogen-bonding to form a double layer (NH···O bond lengths are 3.036, 2.978, 2.857, 2.909, 2.958, and 2.742 Å, respectively). The IR-band assignment of the compound was achieved using the polarized IR-spectroscopy of oriented colloids in a nematic host. Theoretical ab initio calculations were performed and achieved with a view to explain the IR-bands of the H₂Sq.HSq^? motif.     

Crystal structure and spectroscopic properties of A[VO2(SO4)(H2O)2] · H2O (A = K, Rb, Tl, NH4) compounds

The crystal structure of dioxovanadium(V) sulfate trihydrates A[VO₂(SO₄)(H₂O)₂] · H₂O, where A is K, Rb, Tl, or NH₄, has been determined based on a combination of neutron and X-ray diffraction data. The compounds are isostructural and have a monoclinic lattice (space group P2₁, Z = 2) with unit cell parameters a = 6.24535(8), 6.26016(7), 6.25817(5), and 6.2500(1) Å; b = 9.8417(1), 9.99736(8), 9.96217(9), and 9.9742(1) Å; c = 6.52113(8), 6.69303(5), 6.70379(6), and 6.70334(9) Å; β = 106.99(1)°, 107.83(1)°, and 107.83(1)°, 107.99(1)°, respectively. The SO₄ tetrahedra and VO₄(H₂O)₂ octahedra share an oxygen vertex to form infinite isolated chains. Atoms A have CN = 10. IR and Raman spectroscopy data are reported.     

Raman spectroscopic study of aqueous (NH4)2SO4 and ZnSO4 solutions

The Raman spectra of the v₁-SO ₄ ^2– band in 0.5–2.5 molar aqueous (NH₄)₂SO₄ and ZnSO₄ solutions in the temperature range 25–85°C were studied. The molar scattering coefficient of the v₁ band is the same for all forms of sulfate in (NH₄)₂SO₄ and ZnSO₄ solutions and is independent of temperature up to 85°C. The v₁ band profile is symmetrical in (NH₄)₂SO₄ solutions. In ZnSO₄ solutions, a shoulder appears on the high frequency side which increases slightly in intensity with increasing concentration and temperature. This high frequency component is attributed to the formation of the contact ion pair (Zn²⁺·SO ₄ ^2– ). The enthalpy of formation for the contact ion pair is estimated from the Raman data to be approximately 3 kJ-mol^–1 which is in reasonable agreement with measurements by other methods.     

Accidental formation of Gd4(SiO4)2OTe: crystal structure and spectroscopic properties

Designing new functional materials with increasingly complex compositions is of current interest in science and technology. Complex rare‐earth‐based chalcogenides have specific thermal, electrical, magnetic and optical properties. Tetragadolinium bis[tetraoxidosilicate(IV)] oxide telluride, Gd₄(SiO₄)₂OTe, was obtained accidentally while studying the Gd₂Te₃–Cu₂Te system. The crystal structure was determined by means of single‐crystal X‐ray diffraction. The compound crystallizes in the space group Pnma. Three symmetry‐independent gadolinium sites were determined. The excitation and emission spectra were collected at room temperature and at 10 K. Gd₄(SiO₄)₂OTe appears to be a promising optical material when doped with rare‐earth ions.     

Crystal structure and spectroscopic elucidation of 3-phenylpyridinium hydrogensquarate

The novel 3-phenylpyridinium hydrogensquarate (1) has been synthesized and its structure and properties are elucidated spectroscopically, thermally and structurally, using single crystal X-ray diffraction, linear-polarized solid-state IR-spectroscopy, UV-spectroscopy, TGA, DSC, DTA and ESI MS. Quantum chemical calculations were used to obtain the electronic structure, vibrational data and electronic spectrum. 3-Phenylpyridinium hydrogensquarate, crystallizes in the space group P?1 and the ions in the unit cell are joined into layers by intermolecular NH?OC_(Sq) bonds with bond lengths of 2.625 and 2.626 Å, respectively. Hydrogentartarates form dimers by strong OCOH?OCO interactions (2.499 Å).     

Crystal and molecular structure of 2-chlorophenoxyacetyl-4-isopropylbenzene

Institute of Crystallography, Academy of Sciences of the USSR. Physicotechnical Institute, Academy of Sciences of the Tadzhik SSR. Translated from Zhurnal Strukturnoi Khimii, Vol. 31, No. 3, pp. 156–159, May–June, 1990.     

Crystal and molecular structure of 2-methylamino-4-thiazolinone

Conclusions An x-ray diffraction structural analysis showed that 2-methylamino-4-thiazolinone in the crystal exists as the amine tautomer and forms centrosymmetric dimers due to N²-H(N²)...N¹ hydrogen bonds. An intermolecular S...O' contact is found in the direction close to the extension of the S-C¹ bond. The methyl group is in the s-cis position relative to the sulfur atom. Significant -electron delocalization is found over the Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 344–347, February, 1987.