Solubility in the system 2HCOONa + CaCl<Subscript>2</Subscript> ⇄ (HCOO)<Subscript>2</Subscript>Ca + 2NaCl–H<Subscript>2</Subscript>O

Phase and conversion equilibria in the quaternary reciprocal water–salt system 2HCOONa + CaCl₂ ? (HCOO)₂Ca + 2NaCl–H₂O at 25°C were studied for the first time to determine the concentration parameters of the production of calcium formate from sodium formate.     

Synthesis and X-ray diffraction study of Li(H<Subscript>3</Subscript>O)[UO<Subscript>2</Subscript>(C<Subscript>2</Subscript>O<Subscript>4</Subscript>)<Subscript>2</Subscript>(H<Subscript>2</Subscript>O)] · H<Subscript>2</Subscript>O

Single crystals of Li(H₃O)[UO₂(C₂O₄)₂(H₂O)] · H₂O (I) have been synthesized and studied by X-ray diffraction. Compound I crystallizes in the monoclinic crystal system with the unit cell parameters: a = 7.1682(10) Å, b = 29.639(6) Å, c = 6.6770(12) Å, β= 112.3(7)°, space group P 2₁/c, Z = 4, R = 4.36%. Structure I contains discrete mononuclear groups [UO₂(C₂O₄)₂(H₂O)]^2? ascribed to the crystal-chemical group AB ₂ ⁰¹ M¹ (A = UO₂ ²⁺, B⁰¹ =C₂O ₄ ^2? , M¹ = H₂O), which are “cross-linked” by the lithium ions into infinite layers {Li(UO₂)(C₂O₄)₂(H₂O)₂}^? perpendicular to [010]. The hydroxonium ions are located between adjacent uranium-containing layers. A hydrogen bond system involving water molecules, oxalate ions, and hydroxonium combines the anionic layers into a three-dimensional framework.     

Crystal structure of Mg pivalate hydrate Mg(H<Subscript>2</Subscript>O)<Subscript>6</Subscript>(Piv)<Subscript>2</Subscript> · 3H<Subscript>2</Subscript>O

Single crystals of Mg pivalate hydrate, Mg(H₂O)₆(Piv)₂ · 3H₂O (HPiv = (CH₃)₃CCOOH) are synthesized and their structure is determined by X-ray diffraction method. The crystals are rhombic: a = 10.917(2) Å, b = 12.625(2) Å, c = 31.394(8) Å, Z = 8, space group Pbca, R ₁ = 0.0525. The Mg atom has octahedral surrounding of the O atoms of water molecules (Mg-O 2.044–2.137 Å). The cationic chains of [Mg(H₂O)₆] _∞ ²⁺ lie in the voids of doubled network anionic layers of [(H₂O)₃(Piv)₂] _∞∞ ^2? . Inside the layer, the pivalate anions alternate with water molecules in the xy plane, being bonded to them by hydrogen bonds. The cationic chains and the anionic layers are united into layered packs by hydrogen bonds between coordinated water molecules and pivalate anions and between coordinated and crystal hydrate water molecules.     

Synthesis and Crystal Structure of [Co(H<Subscript>2</Subscript>O)<Subscript>6</Subscript>](C<Subscript>19</Subscript>H<Subscript>17</Subscript>O<Subscript>4</Subscript>SO<Subscript>3</Subscript>)<Subscript>2</Subscript>⋅8H<Subscript>2</Subscript>O

The title compound, cobalt 4′,7-diethoxylisoflavone-3′-sulfonate([Co(H₂O)₆](X)₂⋅8H₂O, X = C₁₉H₁₇O₄SO₃) was synthesized and its structure was determined by single-crystal X-ray diffraction analysis. It crystallizes in the triclinic space group P-1 with cell parameters a = 9.026(3) Å, b = 16.431(5) Å, c = 18.195(6) Å, α = 72.289(4)^∘, β = 87.498(4)^∘, γ = 82.775(5)^∘, V = 2550.1(13) Å⁻³, D_c = 1.419 Mg m⁻³, and Z = 2. The results show that the title compound consists of one cobalt cation, six coordinated water molecules, eight lattice water molecules, and two 4′,7-diethoxylisoflavone-3′-sulfonate anions, C₁₉H₁₇O₄SO⁻₃. Two anions have different conformations. Twelve H atoms of six coordinated water molecules, as donors, form hydrogen bonds with four oxygen atoms of sulfo-groups of two anions and eight oxygen atoms of eight lattice water molecules. In addition, π < eqid1 > ⋅ < eqid2 > π stacking interactions exist in the crystal structure, which together with hydrogen bonds lead to supramolecular formation with a three-dimensional network.     

Crystal Structure of Neptunium(V) Acetate [(NpO<Subscript>2</Subscript>)<Subscript>2</Subscript>(OOCCH<Subscript>3</Subscript>)<Subscript>2</Subscript>(H<Subscript>2</Subscript>O)] ⋅ 2H<Subscript>2</Subscript>O

A new neptunium(V) complex [(NpO₂)₂(CH₃COO)₂(H₂O)] ? 2H₂O was synthesized and its crystal structure was determined. The unit cell parameters are: a = 24.007(10) Å, b = 6.779(3) Å, c = 8.076(3) Å, space group Pnma, Z = 4, V = 1314.2(9) ų, R = 0.049, wR(F²) = 0.105. The crystal structure of the compound is composed of neutral [(NpO₂)₂(CH₃COO)₂(H₂O)] layers and molecules of the water of crystallization. Each of the crystallographically independent neptunoyl ions performs a bidentate function thus forming a composite system of cation-cation bonds.     

Thermogravimetric analysis of wheatleyite Na<Subscript>2</Subscript>Cu<Superscript>2+</Superscript>(C<Subscript>2</Subscript>O<Subscript>4</Subscript>)<Subscript>2</Subscript>·2H<Subscript>2</Subscript>O

Evidence for the existence of primitive life forms such as lichens and fungi can be based upon the formation of oxalates. These oxalates form as a film like deposit on rocks and other host matrices. The anhydrous oxalate mineral moolooite CuC₂O₄ as the natural copper(II) oxalate mineral is a classic example. Another example of a natural oxalate is the mineral wheatleyite Na₂Cu²⁺(C₂O₄)₂·2H₂O. High resolution thermogravimetry coupled to evolved gas mass spectrometry shows decomposition of wheatleyite at 255°C. Two higher temperature mass losses are observed at 324 and 349°C. Higher temperature mass losses are observed at 819, 833 and 857°C. These mass losses as confirmed by mass spectrometry are attributed to the decomposition of tennerite CuO. In comparison the thermal decomposition of moolooite takes place at 260°C. Evolved gas mass spectrometry for moolooite shows the gas lost at this temperature is carbon dioxide. No water evolution was observed, thus indicating the moolooite is the anhydrous copper(II) oxalate as compared to the synthetic compound which is the dihydrate.     

Transformations of CO<Subscript>2</Subscript> in Two-Phase Systems C<Subscript>8</Subscript>F<Subscript>18</Subscript>–H<Subscript>2</Subscript>O and C<Subscript>6</Subscript>F<Subscript>6</Subscript>–H<Subscript>2</Subscript>O

The transformation of carbon dioxide in aqueous emulsions of perfluorons in the presence of oxygen in the air results in the formation of a mixture of oxalic acid and a minor set of organic compounds C₄–C₈. The maximum CO₂ consumption occurs in the emulsion with the C₈F₁₈: H₂O vol/vol ratio of 1: 0.42 at pH 2.4; the H₂C₂O₄ yield is 11 mol %.     

Phase and extraction equilibria in H<Subscript>2</Subscript>O–sulfonol–HCl (H<Subscript>2</Subscript>SO<Subscript>4</Subscript>) and H<Subscript>2</Subscript>O–sodium dodecyl sulfate–HCl (H<Subscript>2</Subscript>SO<Subscript>4</Subscript>) systems

Solubility isotherms of water–sulfonol–hydrochloric (or sulfuric) acid and water–sodium dodecyl sulfate–hydrochloric acid systems at 75°C and a water–sodium dodecyl sulfate–sulfuric acid system at 50°C are constructed. Regions of two-phase liquid equilibrium suitable for use in extraction are found. Concentration parameters for extraction are determined. The interfacial distribution of a series of metal ions with and without such additional complexing reagents as diantipyrylmethane and diantipyrylheptane is studied.     

Synthesis and crystal structure of the complex [Nd(2-EOBA)<Subscript>3</Subscript>(phen)(H<Subscript>2</Subscript>O)]<Subscript>2</Subscript> · H<Subscript>2</Subscript>O

A novel lanthanide complex of [Nd(2-EOBA)₃(phen)(H₂O)]₂ · H₂O (2-EOBA = 2-ethoxylbenzoate, phen = 1,10-phenanthroline), has been synthesized and structurally characterized by single crystal X-ray diffraction. The complex crystallizes in monoclinic, space group P2(1)/n with a = 14.7453(18) Å, b = 12.3628(15) Å, c = 19.473(2) Å, α = 90°, β = 93.349(2)°, γ = 90°. Two Nd³⁺ ions are connected together by two bridging 2-EOBA ligands and each Nd³⁺ ion is further coordinated by two chelating 2-EOBA ligands, one chelating phen molecule and one water molecule. The coordination number of Nd³⁺ ion is nine. The coordination geometry of Nd³⁺ ion is a distorted monocapped square-antiprism.     

Crystal structure of Cs[(UO<Subscript>2</Subscript>)<Subscript>2</Subscript>(C<Subscript>2</Subscript>O<Subscript>4</Subscript>)<Subscript>2</Subscript>(OH)] · H<Subscript>2</Subscript>O

Single crystals of Cs[(UO₂)₂(C₂O₄)₂(OH)] · H₂O were synthesized and structurally studied using X-ray diffraction. The compound crystallizes in monoclinic space group P2₁/m, Z = 2, with the unit cell parameters a = 5.5032(4) Å, b = 13.5577(8) Å, c = 9.5859(8) Å, β = 97.012(3)°, V = 709.86(9) ų, R = 0.0444. The main building units of crystals are [(UO₂)₂(C₂O₄)₂(OH)]^? layers of the A₂K ₂ ⁰² M² (A = UO ₂ ²⁺ , K⁰² = C₂O ₄ ^2? , and M² = OH^?) crystal-chemical family. Uranium-containing layers are linked into a three-dimensional framework via electrostatic interactions with outer-sphere cations and hydrogen bonds with water molecules.     

Measurement of mineral solubilities in the ternary systems NaCl−ZnCl<Subscript>2</Subscript>−H<Subscript>2</Subscript>O and MgCl<Subscript>2</Subscript>−ZnCl<Subscript>2</Subscript>−H<Subscript>2</Subscript>O at 373 K

In this work, the solubilities of the salt minerals and the densities of solution in two ternary systems sodium chloride–zinc chloride–water and magnesium chloride–zinc chloride–water were measured at 373 K using an isothermal solution saturation method. Based on the determined equilibrium solubility data and the corresponding equilibrium solid phase, the phase diagrams and density diagrams of the two systems were plotted. The results show that the two ternary systems are complex and the eutectic points, the univariant solubility curves and the solid crystalline phase regions are shown and discussed. The phase diagram of the ternary system NaCl?ZnCl₂?H₂O at 373 K is constituted of two eutectic points, three univariant solubility curves and three solid crystalline phase regions corresponding to NaCl, ZnCl₂ and 2NaCl · ZnCl₂. And the phase diagram of the ternary system MgCl₂?ZnCl₂?H₂O at 373 K includes two eutectic points, three univariant solubility curves and three solid crystalline phase regions corresponding to MgCl₂ · 6H₂O, MgCl₂ · ZnCl₂ · 5H₂O and ZnCl₂. The experimental results were simply discussed.     

The crystal structure of [Mg(H<Subscript>2</Subscript>O)<Subscript>6</Subscript>][VO(edta)] · 3.5H<Subscript>2</Subscript>O

The crystal structure of complex [Mg(H₂O)₆][VO(edta)] · 3.5H₂O (I) was determined by X-ray diffraction study. The crystals are monoclinic, a = 6.779 Å, b = 13.373(6) Å, c = 25.054 Å, β = 96.55°, Z = 4, space group P2₁. The unit cell contains two independent [VO(edta)]^2? anions, two independent [Mg(H₂O)₆]²⁺ cations, and seven crystal-water molecules. The coordination polyhedron of each vanadium atom is formed by five donor atoms of the edta ligand (2N + 3O) (V(1)-N(1), 2.278 Å; V(1)-N(2), 2.149 Å; V(2)-N(3), 2.301 Å; V(2)-N(4), 2.165 Å; V-O(acet), 2.00 ± 0.02 Å) and the oxygen atom of the oxo group (V-O, 1.60 ± 0.01 Å). The edta ligands and the vanadium atom form three glycinate rings: two R-type rings and one G-type ring (one acetate branch remains free), as well as an E-type ring with an asymmetric gauche configuration. The [Mg(H₂O)₆] cations are slightly distorted octahedra (Mg-O, 2.013–2.132 Å, the OMgO angles are 86.6°–94.2°). The H₂O molecules form a bifurcate system of H-bonds. The crystals of compound I belong to OD-type structures with an incomplete ordering of layers.     

Synthesis and crystal structures of [K(H<Subscript>2</Subscript>O)(Piv)]<Subscript>∞</Subscript> and [K<Subscript>2</Subscript>(Phen)(H<Subscript>2</Subscript>O)<Subscript>2</Subscript>(Piv)<Subscript>2</Subscript>]<Subscript>∞</Subscript>

A method for the synthesis of potassium pivalates (trimethylacetates) from potassium tert-butoxide and pivalic acid was proposed. The complexes of the formulas [K(H₂O)(Piv)]_∞(I) and [K₂(Phen)(H₂O)₂(Piv)₂]_∞ (II) (Piv denotes the pivalate anion and Phen denotes 1,10-phenanthroline) were obtained and characterized by elemental analysis and IR and ¹H NMR spectroscopy. The crystal structures of complexes I and II were determined using X-ray diffraction. Crystal structure I has a layered motif with two nonequivalent K atoms (C.N.s 5 + 2 and 6). The coordination of phenanthroline in II gives rise to a ribbon motif, the structure containing three nonequivalent K atoms (C.N.s 6, 6 + 1, and 8).     

Synthesis and crystal structure of complex [Mn(Imdc)<Subscript>2</Subscript>(H<Subscript>2</Subscript>O)<Subscript>2</Subscript>] · 2H<Subscript>2</Subscript>O and its interaction with DNA

Under hydrothermal conditions, the complex [Mn(lmdc)₂(H₂O)₂] · 2H₂O (I) was synthesized and characterized by elemental analysis and IR spectrum (HImdc = 4,5-imidazofedicarboxylic acid). The crystal structure of I was determined by single-crystal X-ray diffraction (crystallizing in the monoclinic crystal system, P ₂/c space group, a = 11.000(2), b = 7.1281(14), c = 12.696(3) Å, β = 122.45(3), Z = 2. In I, the Mn²⁺ ion was chelated by two Imdc with one of their nitrogen atoms and a carboxylic oxygen atom, while two water molecules occupy the axial position of the Mn atom forming a distorted octahedral geometry. Three-dimensional structure of I was formed by intermolecular hydrogen bonds. UV-Vis and fluorescence spectra of I interacting with DNA show that insertion is the main binding mode between I and fish sperm DNA. Gel electrophoresis shows that I cleaves both supercoiled and circular pBR322 DNA to form a small molecular fragment.     

Crystal structure of Ba<Subscript>3</Subscript>[UO<Subscript>2</Subscript>(C<Subscript>2</Subscript>O<Subscript>4</Subscript>)<Subscript>2</Subscript>(NCS)]<Subscript>2</Subscript> · 9H<Subscript>2</Subscript>O

Single crystals of Ba₃[UO₂(C₂O₄)₂(NCS)]₂ · 9H₂O are synthesized and studied by X-ray diffraction. The crystals are orthorhombic, space group Fddd, Z = 16, and the unit cell parameters are a = 16.253(3) Å, b = 22.245(3) Å, c = 39.031(6) Å. The main crystal structural units are mononuclear complex groups [UO₂(C₂O₄)₂NCS]^3? of the crystal-chemical family (AB ₂ ⁰¹ M¹ (A = UO ₂ ²⁺ , B⁰¹ = C₂O ₄ ^2? , M¹ = NCS^?) of the uranyl complexes linked into a three-dimensional framework by electrostatic interactions and hydrogen bonds involving oxalate ions and water molecules.     

Rapid synthesis,kinetics and thermodynamics of binary Mn<Subscript>0.5</Subscript>Ca<Subscript>0.5</Subscript>(H<Subscript>2</Subscript>PO<Subscript>4</Subscript>)<Subscript>2</Subscript> · H<Subscript>2</Subscript>O

The non-isothermal kinetics of dehydration of AlPO₄·2H₂O was studied in dynamic air atmosphere by TG–DTG–DTA at different heating rates. The result implies an important theoretical support for preparing AlPO₄. The AlPO₄·2H₂O decomposes in two step reactions occurring in the range of 80–150 °C. The activation energy of the second dehydration reaction of AlPO₄·2H₂O as calculated by Kissinger method was found to be 69.68 kJ mol⁻¹, while the Avrami exponent value was 1.49. The results confirmed the elimination of water of crystallization, which related with the crystal growth mechanism. The thermodynamic functions (ΔH*, ΔG* and ΔS*) of the dehydration reaction are calculated by the activated complex theory. These values in the dehydration step showed that it is directly related to the introduction of heat and is non-spontaneous process.     

Crystal structure of Cs[Gd(H<Subscript>2</Subscript>O)<Subscript>4</Subscript>Re<Subscript>6</Subscript>Te<Subscript>8</Subscript>(CN)<Subscript>6</Subscript>]·4H<Subscript>2</Subscript>O

The structure of the salt Cs[Gd(H₂O)₄Re₆Te₈(CN)₆]·4H₂O (space group P-1, a = 9.436(5) Å, b = 12.365(7) Å, c = 15.187(8)Å, α = 89.104(10)°, β = 86.996(10)°, γ = 82.304(9)°) has been established by single crystal XRD. The structure of the compound features layers involving Gd³⁺ cations bound to cluster anions [Re₆Te₈(CN)₆]^4? through cyanide groups. The interlayer space contains cesium cations and crystallization water molecules.     

Clathrate [Zn(C<Subscript>6</Subscript>H<Subscript>5</Subscript>COO)<Subscript>2</Subscript>(H<Subscript>2</Subscript>O)<Subscript>2</Subscript>] · 2CH<Subscript>3</Subscript>COOH: Synthesis and crystal structure

The clathrate [Zn(C₆H₅COO)₂(H₂O)₂] · 2CH₃COOH (I) was obtained for the first time from zinc(II) benzoate. The individuality, the unit cell parameters, and the number of “guest” molecules in complex I were determined from X-ray diffraction and derivatographic data. Its crystal structure was solved.     

Molar heat capacity and thermodynamic properties of crystalline [Nd(Glu)(H<Subscript>2</Subscript>O)<Subscript>5</Subscript>(Im)<Subscript>3</Subscript>](ClO<Subscript>4</Subscript>)<Subscript>6</Subscript>·2H<Subscript>2</Subscript>O

A complex of neodymium perchloric acid coordinated with L-glutamic acid and imidazole, [Nd(Glu)(H₂O)₅(Im)₃](ClO₄)₆·2H₂O was synthesized and characterized by IR and elements analysis for the first time. The thermodynamic properties of the complex were studied with an automatic adiabatic calorimeter and differential scanning calorimetry (DSC). Glass transition and phase transition were discovered at 221.83 and 245.45 K, respectively. The glass transition was interpreted as a freezing-in phenomenon of the reorientational motion of ClO₄⁻ ions and the phase transition was attributed to the orientational order/disorder process of ClO₄⁻ ions. The heat capacities of the complex were measured with the automatic adiabatic calorimeter and the thermodynamic functions [H _T-H _298.15] and [S _T-S _298.15] were derived in the temperature range from 80 to 390 K with temperature interval of 5 K. Thermal decomposition behavior of the complex in nitrogen atmosphere was studied by thermogravimetric (TG) analysis and differential scanning calorimetry (DSC).