Synthesis of Pu(V) sulfates

Synthesis of Pu(V) sulfates from aqueous solutions was studied, and previously unknown Co(NH₃)₆PuO₂(SO₄)₂·2H₂O was prepared and characterized by X-ray diffraction analysis. It was found that it is isostructural to neptunyl(V) analog. Thermal behavior of this compound in air was studied, and its IR spectrum was recorded and analyzed. The factors preventing formation of Cs₃PuO₂(SO₄)₂·2H₂O and simple sulfates of the composition (PuO₂)₂SO₄·xH₂O were examined.     

Synthesis and crystal structure of cesium actinide(VI) tricarbonate complexes Cs4AnO<Subscript>2</Subscript>(CO<Subscript>3</Subscript>)<Subscript>3</Subscript>·6H<Subscript>2</Subscript>O,An(VI) = U,Np, Pu

Tricarbonate complexes of hexavalent U, Np, and Pu with outer-sphere cesium cations, Cs₄AnO₂·(CO₃)₃·6H₂O, were synthesized and studied by single crystal X-ray diffraction analysis. Crystals of Cs₄AnO₂·(CO₃)₃·6H₂O consist of [AnO₂(CO₃)₃]^4– complex anions and hydrated Cs⁺ cations. The coordination polyhedron (CP) of An(VI) atoms is a distorted hexagonal bipyramid with three CO ₃ ^2– anions arranged in the equatorial plane. Four independent Cs+ cations have the coordination surrounding in the form of 11-, 10-, and 9-vertex polyhedra formed by the O atoms of CO ₃ ^2– anions, AnO ₂ ²⁺ cations, and water molecules. Six crystallographically independent water molecules in the structure of Cs₄AnO₂(CO₃)₃·6H₂O form a three-dimensional system of hydrogen bonds in which the O atoms of carbonate ions and water molecules act as proton acceptors. The “yl” oxygen atoms of AnO ₂ ²⁺ cations are not involved in hydrogen bonding. The lengths of the An–O_carb bonds in the equator of the U, Np, and Pu hexagonal bipyramids are noticeably influenced by incorporation of the O atoms of the CO ₃ ^2– anions in the coordination polyhedra of Cs⁺ ions and by involvement of these atoms in hydrogen bonding.     

Thaumasite formation in stabilized coal combustion by-products

The by-products of the desulfurization process in a spray drier usually contain a mixture of hannebachite (CaSO₃·1/2H₂O), gypsum (CaSO₄·2H₂O), and the finer fraction of the fly ash. This material was mixed with an additional fly ash and stabilized by adding about 3 wt% lime kiln dust (LKD). The stabilized product was used either as a structural fill or was left in the storage yard for several years. Samples extracted from these sites were analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The analytical results show the formation of thaumasite (Ca₃Si(OH)₆(CO₃)(SO₄)·12H₂O), ettringite (Ca₆Al₂(SO₄)₃(OH)₁₂·26H₂O), and an intermediate phase with varying chemical composition of calcium, aluminum, silicon, and sulfur.     

丁腈橡胶/硫酸高铈复合材料的配位交联反应研究

以四水合硫酸高铈(Ce(SO_4)_2·4H_2O)为配位交联剂,采用原位法制备丁腈橡胶(NBR)/Ce(SO_4)_2·4H_2O复合材料,并利用差示扫描量热分析(DSC)、热重分析(TGA)、溶胀平衡法、扫描电子显微镜(SEM)、硫化仪和万能试验机对其进行结构表征和性能测试。结果表明,Ce(SO_4)_2·4H_2O与NBR发生了配位交联反应,配位硫化为一级反应,活化能为14.4kJ/mol;NBR/Ce(SO_4)_2·4H_2O硫化胶具有良好的力学性能,Ce(SO_4)_2·4H_2O起配位交联和补强填充的作用。配位交联硫化体系具有配方精炼、工艺简单的优点,在特定领域将配位交联NBR替代传统共价交联NBR具有可行性。     

Corrosion behavior of copper T2 and brass H62 in simulated Nansha marine atmosphere

The accelerated corrosion behavior of copper T2 and brass H62 exposed in simulated Nansha marine atmosphere for different periods were investigated by weight loss method, SEM, XRD and potentiodynamic polarization measurements. The results indicate that copper T2 and brass H62 underwent severe corrosion, and the final corrosion rates at 32 days of exposure were 0.24 μm/d and 0.10 μm/d, respectively. Moreover, the overall corrosion type of copper T2 was uniform and the corrosion products Cu₂O and Cu₂Cl(OH)₃ played a vital role in the corrosion rate of copper. While the dezincification corrosion with zinc preferential dissolution was obvious in brass H62. The predominant phases were the zinc-rich compounds Zn₅(OH)₈Cl₂·H₂O, Zn₁₂(SO₄)₃Cl₃(OH)₁₅·5H₂O and NaZn₄(SO₄)Cl(OH)₆·6H₂O. There existed a large number of copper-rich holes with 20–50 μm depth beneath the corrosion product layer.     

Interaction of methanesulfonic acid with actinide ions. The new complexes HImid[Np(C2O4)(CH3SO3)3(H2O)2], [NpO2(Terpy)(CH3SO3)(H2O)]·2H2O, and [UO2(CH3SO3)2(H2O)]

Complexation of methanesulfonic acid with Np(IV), Np(V), and U(VI) ions in aqueous solutions was studied. New crystalline compounds HImid[Np(C₂O₄)(CH₃SO₃)₃(H₂O)₂] (I), [NpO₂(Terpy)(CH₃SO₃)·(H₂O)]·2H₂O (II), and [UO₂(CH₃SO₃)₂(H₂O)] (III) were isolated. The absorption spectra of all the compounds in the IR, visible, and UV ranges were examined. The relationship between the composition, crystal structure, and IR and electronic absorption spectra of the complexes is discussed. Original Russian Text ? G.B. Andreev, N.A. Budantseva, I.G. Tananaev, B.F. Myasoedov, 2009, published in Radiokhimiya, 2009, vol. 51, no. 3, pp. 197–201.     

Octahedral iron phosphate hydroxide microcrystals: Fast microwave-hydrothermal preparation,influencing factors and the shape evolution

Octahedral Fe₄(PO₄)₃(OH)₃ microcrystals have been successfully prepared by a microwave-assisted hydrothermal route at 170 °C for 20 min, employing FeCl₃·6H₂O and NaH₂PO₄·2H₂O as the starting materials in the presence of proper amounts of Na₂SO₃ and acetic acid (HAc). The phase and morphology of the as-prepared product were characterized by means of powder X-ray diffraction (XRD), energy dispersive spectrometry (EDS), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Some factors influencing the formation of octahedral Fe₄(PO₄)₃(OH)₃ microcrystals were systematically investigated, including the reaction temperature, time, and the molar ratio of Na₂SO₃/HAc.     

Synthesis and properties of actinide dimolybdate complexes M<Subscript>2</Subscript>[AnO<Subscript>2</Subscript>(MoO<Subscript>4</Subscript>)<Subscript>2</Subscript>]·H<Subscript>2</Subscript>O (M = Rb,Cs; An = Np,Pu)

New Np(VI) and Pu(VI) dimolybdates Rb₂NpO₂(MoO₄)₂·H₂O (I), Cs₂NpO₂(MoO₄)₂·H₂O (II), Cs₂PuO₂(MoO₄)₂·H₂O (III), and Rb₂PuO₂(MoO₄)₂·H₂O (IV) were synthesized under hydrothermal conditions. The crystal structures of the compounds were determined, and their absorption spectra in the UV, visible, and IR ranges were measured. The compounds crystallize in the monoclinic system. Their crystal structure is based on [AnO₂(MoO₄)₂]_n^2n– anionic layers (An = Np, Pu) formed by (AnO₂)O₅ pentagonal bipyramids and MoO₄ tetrahedra, sharing common vertices. Each An atom in the layer is bonded to other five An atoms via MoO₄ tetrahedra with the formation of a 4343² network. The effect of the ionic radius of the outer-sphere cation on the parameters of the crystal structure and features of the absorption spectra is discussed.     

The phases formed by heating Mn(II) and Zn(II) exchanged α-zirconium phosphate

The phases formed upon heating α-zirconium phosphate, Zr(HPO₄)₂·H₂O, loaded to different levels of Mn(II) and Zn(II) were determined by a combination of thermal and X-ray powder methods. The fully exchanged phases, ZrM(PO₄)₂·4H₂O lose water stepwise at progressively higher temperatures until anhydrous. Above 500°C the X-ray pattern indicates a triphosphate-like phase of the type M_0.5Zr₂(PO₄)₃ is formed. At lower loadings, solid solutions with relatively broad composition regions are observed. The data are summarized in phase diagrams which, however, are not equilibrium diagrams.     

Synthesis and X-ray diffraction study of monohydrates of rubidium and cesium salts of Np(VII) and Pu(VII)

The compounds Rb₃[AnO₄(OH)₂]·H₂O and Cs₃[AnO₄(OH)₂]·H₂O, where An = Np or Pu, were prepared as single crystals by crystallization from alkaline solutions of Np(VII) and Pu(VII) in the course of their drying at 70–75°C. The crystals were subjected to X-ray diffraction analysis. All the compounds are isostructural and contain An atoms in the form of [AnO₄(OH)₂]^3? anions in which the oxygen surrounding of the An atoms is a slightly distorted tetragonal bipyramid. The averaged An-O distances in the equatorial planes of the bipyramids vary insignificantly (within 1.884–1.892 Å), tending to slightly decrease in going from Np to Pu. This trend is more pronounced for averaged An-OH distances, which vary in the range 2.328–2.368 Å. That is, as in the case of the other previously studied An(VII) compounds, the actinide contraction is mainly manifested in shortening of the An-OH distances. One of the features of Rb₃[AnO₄(OH)₂]·H₂O and Cs₃[AnO₄(OH)₂]·H₂O structures, as compared with the trihydrates, is the lack of the symmetry center in [AnO₄(OH)₂]^3? anions.     

Preparation of new zirconium phosphates by solvothermal reaction

Two types of new zirconium phosphates, [enH₂]Zr(OH)(PO₄)(HPO₄) (en; ethylene diamine) and (NH₄)₅[Zr₃(OH)₉(PO₄)₂(HPO₄)] were prepared under solvothermal condition using diethylene glycol as a solvent and their crystal structures were determined by using single crystal X-ray diffraction data. The former compound has the layer structure similar to that of γ-Zr(PO₄)(H₂PO₄) · 2H₂O, and protonated ethylene diamines were located in the interlayer space. At elevated temperatures, this compound decomposed by releasing protonated ethylene diamines and finally changed to ZrP₂O₇. The interlayer space was soft-chemically inactive unlike α-Zr(HPO₄)₂ · H₂O and γ-Zr(PO₄)(H₂PO₄) · 2H₂O. The later compound has the tunnel structure built up by corner-sharing ZrO₆ octahedra and PO₄ tetrahedra, and NH₄ ⁺ ion was located in the tunnel.     

Synthesis and characterisation of infinite coordination networks with 1,6-bis(4-pyridyl)hexane and copper nitrate

Crystallisation of 1,6-bis(4-pyridyl)hexane (Py₂C₆H₁₂) with copper nitrate gives two different phases. Phase 1 of composition [Cu(Py₂C₆H₁₂)₃(NO₃)₂]·2[Cu(Py₂C₆H₁₂)₂(H₂O)(NO₃)]·2(NO₃)·EtOH consists of two different infinite chains in a 1:2 ratio that are interlocked. Hydrogen bonds link chains I to II and chains II to II. In contrast phase 2 of composition [Cu₂(Py₂C₆H₁₂)₄(H₂O)₂]·(NO₃)₄·(Py₂C₆H₁₂)·(EtOH)·2(H₂O) is based upon an infinite 3D framework. It consists of four interpenetrating 3D networks that are crystallographically equivalent.     

DC electrical conductivity of CoSiF6·6H2O and (NH4)2SO4

D.C. electrical conductivity of single crystals of (NH₄)₂SO₄ and CoSiF₆·6H₂O have shown conductivity jump near their respective structural transition temperature. Activation energy of (NH₄)₂SO₄ has been found to be consistent with the earlier data. However, CoSiF₆·6H₂O has given prolonged aging effect due to dipolar relaxation and formation of space charge polarisation.σ _true andP _max have been measured.P _max has shown a negative maximum at the transition point. Activation energy of ZnSiF₆·6H₂O has been found to be comparable with CoSiF₆·6H₂O.     

Chemical Thermodynamics of the Compounds AIIUO2(SO4)2·nH2O (AII = Mn, Fe, Co, Ni, Cu, Zn)

The standard enthalpies of formation of anhydrous 3d transition metal uranyl sulfates and their pentahydrates at 298.15 K were determined by reaction calorimetry. The heat capacities of the compounds A^IIUO₂(SO⁴)₂·5H₂O (A^II = Mn, Fe, Co, Ni, Cu, Zn) and CuUO₂(SO₄)₂ at 7– 300 K were determined by adiabatic vacuum calorimetry, and the thermodynamic functions of these compounds were calculated. The standard entropies and Gibbs energies of formation of these compounds at 298.15 K were determined. The thermodynamics of dehydration of A^IIUO₂(SO₄)₂·5H₂O and of the precipitate-solution equilibria involving these compounds were studied. __________ Translated from Radiokhimiya, Vol. 47, No. 2, 2005, pp. 110–122. Original Russian Text Copyright ? 2005 by Karyakin, Knyazev, Gavrilova.     

Structure refinement and thermal stability of creedite

The crystal structure of the mineral creedite (hydrous calcium aluminum sulfate fluoride, Ca₃Al₂(F,OH)₁₀(SO₄) · 2H₂O) has been determined by Rietveld powder diffraction analysis. X-ray diffraction data obtained in the temperature range from 25 to 470°C indicate that the crystal structure of creedite is stable up to 390°C. We have measured the unit-cell parameters of creedite as functions of temperature and determined its thermal expansion coefficients. Above 390°C, the mineral decomposes.     

Synthesis of Cu3(PO4)2 · H2O based solid solutions through Co or Ni substitution for Cu

New substitutional solid solutions have been synthesized: (Cu_{1 ? x} Co_x)₃(PO₄)₂ · H₂O (0 < x ≤ 0.20), (Cu_{1 ? x} Ni_x)₃(PO₄)₂ · H₂O (0 < x ≤ 0.12), and (Cu_{1 ? y} Co_y)₃(PO₄)₂ · H₂O (0.55 ≤ y ≤ 0.65). The first two solid solutions are isostructural with Cu₃(PO₄)₂ · H₂O (monoclinic symmetry, sp. gr. C2/c); the third solid solution also has a monoclinic structure, which is a Cu₃(PO₄)₂ · H₂O related superstructure. The lattice parameter b of (Cu_{1 ? y} Co_y)₃(PO₄)₂ · H₂O (0.55 ≤ y ≤ 0.65) is almost twice that of (Cu_{1 ? x} Co_x)₃(PO₄)₂ · H₂O (0 < x ≤ 0.20), while their a and c parameters differ little. The solid solutions have been characterized by chemical analysis, x-ray diffraction, IR spectroscopy, and thermal analysis.     

Disordering of Pentacesium Trihydrogen Tetrasulfate in Cs5H3(SO4)4–SiO2 Composite Proton Electrolytes

(1 – x)Cs₅H₃(SO₄)₄ · yH₂O–xSiO₂ composite electrolytes were prepared in the composition range x = 0.3–0.9 and were characterized by impedance measurements, differential scanning calorimetry, and x-ray diffraction analysis. The results indicate that the introduction of fine SiO₂ particles stabilizes the high-conductivity, disordered (nearly amorphous) state of the salt, which is similar to that in pure Cs₅H₃(SO₄)₄ above the phase transition (>420 K). The conductivity of the composites is independent of SiO₂ content up to x = 0.7 and decreases at x 0.8 owing to percolation disruption. The disordering of Cs₅H₃(SO₄)₄ · yH₂O is reversible and is due to changes in the content of water of hydration.     

Simulating study of atmospheric corrosion of Zn-Al alloy coating in industrial zone: Structure and properties of zinc hydroxysulfate rust particles prepared in the presence of Al(III)

In order to simulate the atmospheric corrosion of Zn-Al alloy coating on the steels in industrial zone, zinc hydroxysulfate (Zn₄(OH)₆(SO₄)·nH₂O: ZHS) rust was artificially synthesized by hydrolyzing the ZnO particles in a mixture of aqueous ZnSO₄ and Al₂(SO₄)₃ solutions and the structure and properties of the products were examined by various means. Then, the atomic ratio X_Al?=?Al(III)/(Zn(II)?+?Al(III)) in the solution was ranged from 0 to 1.0. Adding Al(III) decreased the solution pH before aging to inhibit rust formation. Added Al(III) was easily incorporated in the particles than Zn(II). Increasing X_Al turned the major rust following as hexagonal plate-like ZHS particles?→?hexagonal plate-like Zn-Al layered double hydroxide (LDH) particles?→?cubic Al₆O₅(SO₄)₄·H₂O particles. These rust particles possessed a high adsorption affinity to corrosive CO₂ gas. From these results, it can be supposed that atmospheric corrosion of Zn-Al alloy coating on the steels in industrial district produces the dense and compact rust layer composed of plate-like ZHS and/or Zn-Al-LDH particles owing to their preferred orientation to suppress further corrosion of steels.     

Adsorption and Separation of <Superscript>152+154</Superscript>Eu(III) and <Superscript>60</Superscript>Co(II) Using Cerium(IV) Tungstate

Samples of cerium(IV) tungstate (CeW) inorganic ion exchanger were synthesized using different Ce(IV) salts: (NH₄)₂Ce(NO₃)₆·2H₂O, (NH₄)₄Ce(SO₄)₄·2H₂O, and Ce(SO₄)₂·4H₂O. The samples were characterized using FT-IR and X-ray diffraction. The adsorption behavior of ^152+154Eu(III) and ⁶⁰Co(II) on CeW was studied under batch and dynamic conditions. Factors influencing the adsorption kinetics were examined. Loading and elution behavior of both ions was studied using different eluents. Complete separation of Eu(III) and Co(II) (^152+154Eu and ⁶⁰Co tracers) was achieved using small columns packed with CeW.     

Preparation of (NH4)Zr2(PO4)3 and HZr2(PO4)3

(NH₄)Zr₂(PO₄)₃ has been prepared, hydrothermally, from α-zirconium phosphate in three different ways; (1) from amine intercalates at 300°C, (2) from mixtures of ZrOCl₂·8H₂O in excess (NH₄)H₂PO₄ and (3) reaction of NH₄Cl with Zr(NaPO₄)₂. Ammonium dizirconium triphosphate is rhombohedral with a = 8.676(1) and $\text{c}\text{= 24.288(5)}\text{A}\text{?}$. It decomposed on heating to HZr₂(PO₄)₃. Below 600°C a complex, as yet unindexed, X-ray pattern was obtained. A very similar X-ray pattern was obtained by washing LiTi_0.1Zr_1.9(PO₄)₃ with 0.3N HCl. Heating this phase or NH₄Zr₂(PO₄)₃, above 600°C resulted in the appearance of a rhombohedral phase of HZr₂(PO₄)₃ with cell dimensions a = 8.803(5) and $\text{c}\text{= 23.23(1)}\text{A}\text{?}$. The protons were not completely removed until about 1150°C. Decomposition of (NH₄)Zr₂(PO₄)₃ at 450°C yielded an acidic gas whereas at 700°C NH₃ was evolved. A possible explanation for this behavior is presented.