Synthesis and thermochemical characteristics of Na2O · Al2O3 · 2.5H2O

A pure phase of monosodium aluminate hydrate Na₂O · Al₂O₃ · 2.5H₂O (MAH) is synthesized and characterized by means of XRD, IR, SEM, TGA, and DSC. The heat capacity of the compound is measured in the temperature range of ?100 to 100°C, and the thermal contributions to enthalpy and entropy are calculated. The standard entropy, enthalpy, and Gibbs energy of formation of MAH at 298 K are estimated.     

Synthesis and crystal structure of the lithium perrhenate monohydrate LiReO4·H2O

A new monohydrate of lithium perrhenate LiReO₄·H₂O was prepared by dehydration of LiReO₄·1.5H₂O at room temperature. The single crystals of LiReO₄·H₂O were obtained by crystallisation from the isoamyl acetate solution of LiReO₄·1.5H₂O. The structure of monohydrate (a=5.6674(4), b=10.771(1), c=7.4738(7) Å, β=102.422(7)°, R₁=0.0414, space group P2₁/a, Z=4) is built up from LiO₃(H₂O)₂ trigonal bipyramids and ReO₄ tetrahedra sharing common edges and corners inside the layers. The layers are connected together by hydrogen bonds. The relationships between the structures of sesquihydrate, monohydrate and anhydrous LiReO₄ are discussed.     

X-ray powder structure determination of Li6P6O18·3H2O

Preparation, characterization by X-ray diffraction, IR absorption, DTA-GTA analysis and ab-initio crystal structure determination are reported for a new lithium cyclohexaphosphate hydrate Li₆P₆O₁₈·3H₂O. It crystallizes in a trigonal (rhomboedral) cell (space group R 3¯m No 166, Z = 6) with a = 15.7442(2) Å, c = 12.5486(2) Å. X-ray powder diffraction pattern data was refined by Rietveld profile technique and lead to R_Bragg = 0.09. The crystal structure of Li₆P₆O₁₈·3H₂O is built up from [P₆O₁₈]^6- ring anions, having the 3m symmetry, alternating along the 3¯ axis with rings made of six LiO₄ tetrahedra and six LiO₅ pseudo square pyramids sharing common edges.     

Synthesis and properties of Na6[Pb(S2O3)4] · 6H2O

Conditions for the synthesis of the water-soluble lead thiosulfate complex Na₆[Pb(S₂O₃)₄] · 6H₂O were determined. The complex synthesized was characterized by UV and IR spectroscopy and X-ray phase and thermal analyses. Thermolysis schemes were proposed on the basis of the IR and mass spectra of the thermal decomposition products.     

Hexaaquachromium(III) trihydrogen isopolyvanadate [Cr(H2O)6]H3[V10O28] · 2H2O: Synthesis and study

Hexaaquachromium(III) trihydrogen isopolyvanadate [Cr(H₂O)₆]H₃[V₁₀O₂₈] · 2H₂O (I) was obtained and examined by mass spectrometry, X-ray powder diffraction, thermogravimetry, and IR and NMR spectroscopy. The crystals are monoclinic, space group $P\bar 1$ a = 7.862(3), b = 8.427(5), c = 5.000(2) Å, β = 96.46(4)°, V = 867.0(3) ų, ρ_calcd = 5.83 g/cm³, Z = 1.     

LiO Raman Bands of 6Li2CO3 and 7Li2CO3

The Raman spectra of polycrystalline ⁶Li₂CO₃ have been recorded in the frequency region from 600 to 300 cm⁻¹. Four very weak bands have been observed for each compound the isotopic frequency shifts are reported. The results have been compared with those from the i.r. spectra for the LiO₄ tetrahedra.     

Synthesis and physicochemical study of diazabicycloundecene hexamolybdochromate [C9H16N2]H3[CrMo6O18(OH)6] · 2H2O

Quinazoline hexamolybdochromate [C₉H₁₆N₂]H₃[CrMo₆O₁₈(OH)₆] · 2H₂O has been synthesized and studied by mass spectroscopy, X-ray powder diffraction, thermogravimetry, and IR and NMR spectroscopy. The compound crystallizes in triclinic system with the unit cell parameters a = 15.06 Å, b = 13.08 Å, c = 8.17 Å, α = 59.85°, β = 123.15°, γ = 107.01°, V = 1165.62 ų, ρ_pycn = 3.58 g/cm³, and Z = 2.     

Synthesis and crystal structure of ((NH3CH2CH2)3N)2P6O18·6H2O

Chemical preparation and crystal structure are given for a new cyclohexaphosphate: ((NH₃CH₂CH₂)₃N)₂P₆O₁₈·6H₂O. This compound is triclinic P¯1 with the following unit-cell parameters: a = 10,281(1)Å, b = 11.083(1)Å, c = 9.307(2)Å, α = 103.83(1) °, β = 108.56(1) °, γ = 68.11(1) °, Z = 1, V = 924.2(3)ų and pcal. = 1.582 g.cm⁻³. Its atomic arrangements contain layers built by P₆O₁₈ ring anions spreading in the plans (001). Between these layers are located the organic groups which form hydrogen bonds with oxygen atoms of P₆O₁₈ rings and water molecules. Crystal structure has been solved and refined to R = 0.028 using 4540 independent reflections. The thermal behavior has been investigated and interpreted by comparison with IR absorption spectroscopy and X-ray diffraction experiments.     

The Synthesis and Characterization of [4-CH3OC6H4CH2NH3]4P2O7·6H2O

Inorganic–organic hybrid compounds exhibit interesting properties in several application areas. In this regard, chemical preparation and characterization by X-ray diffraction, thermal analysis, and IR spectroscopy are given for a new organic cation diphosphate [4-CH₃OC₆H₄CH₂NH₃]₄P₂O₇·6H₂O. This later crystallizes in a C2/c unit cell with a = 38.238(6)Å, b = 6.453(1)Å, c = 16.942(7)Å; β = 97.60(4)°; Z = 4; and V = 4144(2)ų and D_x = 1.377 g·cm^?3. Its crystal structure has been determinated and refined to R = 0.044, using 7978 independent reflections. This atomic arrangement consists of inorganic layers built up from P₂O₇ ^4? anions and water molecules. On these layers, which are parallel to the (b, c) planes, the (4-CH₃OC₆H₄CH₂NH₃)⁺ cations are anchored through multiple hydrogen bonds.     

Thermodynamic properties of two zinc borates: 3ZnO·3B2O3·3.5H2O and 6ZnO·5B2O3·3H2O

Two pure zinc borates with microporous structure 3ZnO·3B₂O₃·3.5H₂O and 6ZnO·5B₂O₃·3H₂O have been synthesized and characterized by XRD, FT-IR, TG techniques and chemical analysis. The molar enthalpies of solution of 3ZnO·3B₂O₃·3.5H₂O(s) and 6ZnO·5B₂O₃·3H₂O(s) in 1 mol · dm⁻³ HCl(aq) were measured by microcalorimeter at T = 298.15 K, respectively. The molar enthalpies of solution of ZnO(s) in the mixture solvent of 2.00 cm³ of 1 mol · dm⁻³ HCl(aq) in which 5.30 mg of H₃BO₃ were added were also measured. With the incorporation of the previously determined enthalpy of solution of H₃BO₃(s) in 1 mol · dm⁻³ HCl(aq), together with the use of the standard molar enthalpies of formation for ZnO(s), H₃BO₃(s), and H₂O(l), the standard molar enthalpies of formation of −(6115.3 ± 5.0) kJ · mol⁻¹ for 3ZnO·3B₂O₃·3.5H₂O and −(9606.6 ± 8.5) kJ · mol⁻¹ for 6ZnO·5B₂O₃·3H₂O at T = 298.15 K were obtained on the basis of the appropriate thermochemical cycles.     

An analysis of the vibrational frequencies and amplitudes of the H5O+2 ion in H4SiW12O40·6H2O (TSA·6H2O) and H3PW12O40·6H2O (TPA·6H2O)

The infrared, Raman and inelastic neutron scattering (INS) spectra of TSA·6H₂O and TPA·6H₂O are in agreement with those expected for the presence of H₅O⁺₂ ions. Force fields for different assignment schemes are compared with the observed vibrational frequencies and the INS spectral profile. All but two schemes are eliminated. Whilst low-resolution INS spectroscopy cannot distinguish between these two schemes, the orientations of the vibrational ellipsoids for one scheme are in better agreement with those reported from low-temperature crystallographic studies of the H₅O⁺₂ ion.     

Synthesis and Crystal Structure of a Hydrogen-bonded Supramolecular Compound [(C6H5N2O)3·Cu1.5]·6H2O

A hydrogen-bonded supermolecular compound [(C6H5N2O)3·Cu1.5](6H2O was syn- thesized from picolinamide and Cu(NO3)2·6H2O at the presence of sodium pyrophosphate deca- hydrate. It crystallizes in triclinic, space group P with a = 1.05947(8), b = 1.09130(8), c = 1.11456(8) nm, α = 67.8460(10), β = 84.497(1), γ = 74.6210(10)°, C18H27Cu1.5N6O9, Mr = 566.77, V = 1.15077(15) nm3, Z = 2, Dc = 1.636 g/cm3, F(000) = 585, μ = 1.461 mm-1, R1 = 0.0278 and wR2 = 0.0749. In the complex, the Cu(II) ion reveals a distorted tetradentate plane-tetragonal geometry. The structure consists of neutral two-dimensional layers via hydrogen bonds O-H…O and N-H…O between the molecules, and the layers are connected by weak interactions of the Cu-Cu, Cu-N, π-π and hydrogen bonds to form a three-dimensional network structure.     

Synthesis, crystal structure, and thermal analysis of hexahydrogen dodecavanadate of composition [NH3 · H2O]6 · H6[Ca4V12O40] · 6H2O

Dihydrogen dodecavanadate of composition [NH₃ · H₂O]₆ · H₆[Ca₄V₁₂O₄₀] · 6H₂O was synthe-sized and studied by X-ray crystallography and TGA analyses. The crystals are cubic, space group I $\bar 4$ 3m;; unit cell parameters: a = 13.518(2) ?, V = 2470.4(3) ?³, ??_calc = 2.2334 g/cm³, Z = 2.     

Synthesis and crystal structure of KBi(C6H4O7) · 3.5H2O

A novel compound, KBi(C₆H₄O₇) · 3.5H₂O (I), has been synthesized in the Bi(NO₃)₂-K₃(HCit) system (HCit^3? is an anion of citric acid C₆H₈O₇) at a component ratio (n) of 8 in a water-glycerol mixture, and its crystal structure has been determined. The crystals are unstable in air. The crystals are triclinic: a = 7.462 Å, b = 10.064 Å, c = 17.582 Å, α = 100.27°, β = 99.31°, γ = 105.48°, V = 1221.2 ų, Z = 2, space group $P\bar 1$ . In the structure of I, asymmetric binuclear fragments [Bi₂(Cit^4?)₂(H₂O)₂]^2? are linked through inversion centers into polymeric chain anions. Ions K⁺ and crystal water molecules are arranged in channels between the chains. The Bi(1)...Bi(2) distances in the binuclear fragment are 4.62 Å, and the Bi(1)...Bi(1) and Bi(2)...Bi(2) distances between bismuth atoms in the chain are 5.83 and 5.95 Å, respectively. The chains are linked through bridging oxygen atoms of the ligands Cit to form layers. In the centrosymmetric four-membered chelate ring Bi₂O₂ formed through Bi-O(Cit) bonds, the distances Bi(1)-Bi(1) are equal to 4.55 Å, and Bi(1)-O are 2.66 and 2.84 Å. The Bi-O bond lengths in I are in the range 2.12–3.16 Å. The Cit ligands act as hexadentate chelating/bridging ligands.     

Structural and Physicochemical Studies of [4-ClC6H4CH2NH3]4Li2P6O18·4H2O

The crystal structure of a new organic cation cyclohexaphosphate, [4-ClC ₆ H ₄ CH ₂ NH ₃ ] ₄ Li ₂ P ₆ O ₁₈ .4H ₂ O, is reported. It crystallizes in the triclinic system (space group P-1) with the following unit-cell parameters: a = 9.628(8), b = 12.801(9), c = 19.528(6) Å, α = 78.60(4)°, β = 83.00(5)°, β = 89.98(4)°, Z = 2, and V = 2341(3)Å ³ . The structure has been solved using direct methods and refined by least-squares analysis [R ₁ = 0.043, wR ₂ = 0.108]. The structure can be described as infinite anionic layers with composition of [Li ₂ (P ₆ O ₁₈ )(H ₂ O) ₄ ] ^{4 ?} and parallel to the ac plane. The organic groups are located in the accessible voids. The molecules are stabilized by O─H…O and N─H…O types of intermolecular hydrogen bonds in the unit cell in addition to Van der Waals forces.     

Li2Mg(ZrF6)2 · 4H2O: Synthesis, X-ray crystallographic, thermal, and MAS NMR study

A new zirconate with lithium and magnesium cations of composition Li₂Mg(ZrF₆)₂ · 4H₂O (I) has been synthesized and studied by different methods (X-ray crystallography, differential thermal analysis, IR spectroscopy, and NMR (¹H, ⁷Li, ¹⁹F, including ¹⁹F MAS NMR). The framework structure of I is composed of edge- and vertex-sharing ZrF₈ dodecahedra, Mg(O_w)₂F₄ octahedra, and Li(O_w)F₄ square pyramids. The structure is additionally stabilized by O-H...F and O-H...O hydrogen bonds. Compound is dehydrated in one stage in the temperature range 105–200°C to form Li₂Mg(ZrF₆)₂ (II). The latter undergoes irreversible phase transition at 365°C leading to its decomposition into a mixture of MgZrF₆ (cubic) and Li₂ZrF₆ (hexagonal). According to IR and NMR data, the structure of fluorozirconate chains of compound I is retained after dehydration.     

Synthesis and Structure of Trinuclear Iron Acetate [Fe3O(CH3COO)6(H2O)3][AuCl4]·6H2O

Iron acetate of composition [Fe₃O(CH₃COO)₆(H₂O)₃][AuCl₄]·6H₂O (I) was synthesized and investigated by X-ray diffraction analysis and Mössbauer spectroscopy. The [Fe₃O(CH₃COO)₆(H₂O)₃]⁺ complex cation has a structure typical for ₃-O bridged trinuclear ferric compounds with iron atoms lying at the vertices of a regular triangle with an oxygen atom at the center. The iron atoms are each coordinated by 4 oxygen atoms of the four bridging carboxylic groups, the ₃-O bridging atom, and the coordinated water molecule in the trans-position to the latter. In the trinuclear cation, the Fe(III) ions are coupled by antiferromagnetic exchange interactions with the exchange parameter J = -29.0 cm ^–1 (HDVV model for D _3h symmetry). The specific role of the solvate water molecules in structure formation is discussed.     

Hydrothermal Synthesis and Crystal Structure of [H4As8V14O42(H2O)]·6H2O

The title compound [H4As8V14O42(H2O)]·6H2O 1 has been synthesized and characterized by elemental analysis, IR, and single-crystal X-ray diffraction analysis. It crystallizes in trigonal, space group R3c with a = b = 36.447(6), c = 21.485(5) (A), V = 24717(8) (A)3, Z = 18, Mr = 2114.66, Dc = 2.557g/cm3, F(000) = 17928, μ = 7.149 mm-1, R = 0.0792 and wR = 0.1265. The [H4As8V14O42- (H2O)] cluster consists of fourteen VO5 square pyramids linked by four As2O5 handle-like units.     

Synthesis and structure of [Cr3O(CH3COO)6(H2O)3][UO2 (CH3COO)3] · 3H2O

Crystals of [Cr₃O(CH₃COO)₆(H₂O)₃][UO₂(CH₃COO)₃]·3H₂O (I) were synthesized for the first time and studied by X-ray crystallography. The crystals of I are orthorhombic: a = 8.3561(3) ?, b = 16.8421(5) ?, c = 25.7448(9) ?, V = 3623.2(2) ?³, space group P2₁2₁2₁, Z = 4, R = 0.0409. The structure is composed of trinuclear [Cr₃O(CH₃COO)₆(H₂O)₃]⁺ complexes and mononuclear [UO₂(CH₃COO)₃]^? complexes classified with crystal-chemical groups A₃M³B ₆ ² M ₃ ¹ (A = Cr³⁺, M³ = O^2?, B² = CH₃COO^?, M¹ = H₂O) and AB ₃ ⁰¹ (A = UO ₂ ²⁺ , B⁰¹ = CH₃COO^?), respectively. The complexes are bound to each other by electrostatic interactions and hydrogen bonds involving outer-sphere water molecules. The results of IR spectroscopic study of I are in good agreement with the structural data for the crystal.