Phase complex of a NaCl—KCl—SrCl<Subscript>2</Subscript>—Sr(NO<Subscript>3</Subscript>)<Subscript>2</Subscript> four-component system and the physicochemical properties of a eutectic mixture

Tree of phases and crystallization were plotted via a priori prediction, and the coordinates (composition) of a nonvariant point of a NaCl-KCl-SrCl₂-Sr(NO₃)₂ four-component system were determined according to calculations and experimental data. The promise of the method for determining the coordinates of nonvariant points in multicomponent systems was confirmed experimentally. The dependence of density and electroconductivity vs. temperature was studied. The volume dilation of a melt was calculated up to the maximum operating temperature.     

水滑石晶体长厚比及晶粒尺寸控制方法研究

层状双金属氢氧化物（LayeredDoubleHydrox－ides，简称LDH）是一类重要的无机晶体材料，因其具有层状结构以及层板元素的可调控性和层间阴离子的可交换性，在催化、离子交换、吸附、医药犤１～８犦等方面具有广泛的用途，已受到人们越来越广泛的关注。近年来，随该类材料应用领域的不断拓展，在许多情况下要求LDH晶体具有小的粒径尺寸，以便最大限度地发挥其功能性。例如将LDH作为阻燃剂犤９犦使用，小粒径粉体可增强与聚合物基材的相容性，提高材料的阻燃、抑烟和力学性能。另一方面，因LDH具有层状结构，在复合材料中其层板能有效…     

Co(NO3)2-(CH3)2SO-H2O system at 25°C

The solubilities and nature of solid phases in the Co(NO₃)₂-(CH₃)₂SO-H₂O system were studied at 25°C. A new congruently saturating compound was recovered: Co(NO₃)₂ · 4(CH₃)₂SO · 2H₂O. The concentration boundaries of its crystallization in the system were determined. The compound was studied by the Schreinemakers wet residue method, X-ray powder diffraction, differential thermal analysis, crystal-optical analysis, and IR spectroscopy.     

Phase complex of the LiCl-NaCl-SrCl2-Sr(NO3)2 four-component system and the physicochemical properties of its eutectic mixture

The crystallization path was designed for the LiCl-NaCl-SrCl₂-Sr(NO₃)₂ four-component system for the first time using a priori prediction, and the coordinates (composition) of the invariant point were determined. The potential of a priori prediction for calculating the coordinates of invariant points in multinary systems was verified experimentally. The density, electrical conductivity, and volume expansion of melts were studied as functions of temperature, and the corrosion rate was studied as a function of the number of heating/cooling cycles.     

Etude de l’isotherme 25°C du système quasi quaternaire H2O-Zn(NO3)2·6H2O-Cu(NO3)2·3H2O-NH4NO3;I- Isoplèthes 4 masse% NH4NO3, 8 ma

The solid-liquid equilibria of the quasi-quaternary system H₂O-Zn(NO₃)₂·6H₂O-Cu(NO₃)₂·3H₂O-NH₄NO₃ were studied at 25°C by using a synthetic method based on conductivity measurements. Three isoplethic sections has been established at 25°C and the stable solid phases which appear are: NH₄NO₃(IV), Zn(NO₃)₂·6H₂O, anhydrous Cu(NO₃)₂, Cu(NO₃)₂·3H₂O and metastable Cu(NO₃)·2.5H₂O. Neither double salts, nor mixed crystals are observed at these temperatures and composition range.     

Ion pairing in H<Subscript>2</Subscript>O and D<Subscript>2</Subscript>O solutions of lead nitrate,as determined with <Superscript>207</Superscript>Pb NMR spectroscopy

The temperature and concentration dependences of ²⁰⁷Pb NMR chemical shifts of Pb(NO₃)₂ in D₂O are reported. The results are analyzed in terms of exchange between a solvated lead ion and the Pb(NO₃)⁺ contact-ion pair. Predictions of the chemical shift difference between the aquated ion and contact-ion pair are carried out for the gas-phase entities and for the solvated species with a DFT calculation. Previously reported data on ²⁰⁷Pb NMR chemical shifts of Pb(NO₃)₂ in H₂O are reevaluated. From the analysis, the enthalpy of dissociation of the contact-ion pair is found to be–42.3±1.0 kJ/mol.     

Some remarks on the extraction of Pu(IV) and Th with tridodecylamine from nitric acid soil leach solutions and the possible existence of a univalent anionic Th-nitrate complex

The extraction of Pu(IV) and Th with tridodecylamine—xylene mixtures from about 6M nitric acid soil leach solutions was studied as a function of the chemical composition of the aqueous phase (iron and calcium concentration, acidity) and the amine concentration in the extractant. No correlation was found between the partition coefficients of Pu(IV) and Th and the composition parameters mentioned above at any of the amine concentrations examined. The slope, in a bilogarithmic plot, of the partition coefficients versus the amine concentrations was found to be close to 2 for Pu(IV) as well as Th in pure 6.5M nitric acid solution, thus indicating the presence of the complexes Pu(NO₃) ₆ ²⁻ and Th(NO₃) ₆ ²⁻ in the extract. When the pure nitric acid solution was replaced by soil leach solutions of similar molarity in HNO₃, the slope remained 2 for Pu(IV), but changed to 1.5 for Th. A possible reason for this slope yielded by Th may be the coexistence of the complexes Th(NO₃) ₆ ²⁻ and Th(NO₃) ₅ ⁻ in the extraction phase. Presented at the 4th SAC Conference on Analytical Chemistry, Birmingham 1977.     

Photolysis of alkaline-earth nitrates

Peroxynitrite and nitrite ions are the diamagnetic products of photolysis (with light at a wavelength of 253.7 nm) of alkaline-earth nitrates; the paramagnetic products and hydrogen peroxide were not found. The structural water in alkaline-earth nitrate crystals did not affect the qualitative composition of the photodecomposition products. The quantum yield of nitrite ions was 0.0012, 0.0038, 0.0078, and 0.0091 quanta^?1 and that of peroxynitrite ions was 0.0070, 0.0107, 0.0286, and 0.0407 quanta^?1 for Sr(NO₃)₂, Ba(NO₃)₂, Ca(NO₃)₂ · 4H₂O, and Mg(NO₃)₂ · 6H₂O, respectively.     

Physico-chemical characterization of thermal decomposition course in zinc nitrate-copper nitrate hexahydrates

This study reports experimental investigations by non-isothermal TG/DSC analysis of Zn(NO₃)₂·4H₂O, Cu(NO₃)₂·4H₂O and their mixtures of known compositions in the temperature range 30–1200°C. Solid/liquid transitions in the sealed samples of the hexahydrate salts and their mixtures were also studied by DSC in the temperature range 0–60°C. The mixture with composition 0.85Zn(NO₃)₂·6H₂O+0.15Cu(NO₃)₂·6H₂O showed single melting peak at 29°C. This mixture was chosen for detailed studies. Melting temperature and heat of fusion of single salt hexahydrates and of the mixture were calculated from DSC endotherms. The different stages in the thermal decomposition processes have been established. The intermediate and the final solid products of the thermal decomposition were analyzed by XRD. The scheme and the decomposition temperature depended on the composition of the starting material. The final decomposition products were CuO (monoclinic), Cu₂O (cubic), ZnO (hexagonal) and their mixtures with the defined crystalline structures. Possible influence of the addition of CuCl₂·2H₂O into the mixture 0.85Zn(NO₃)₂·6H₂O+0.15Cu(NO₃)₂·6H₂O and a gel combustion technique of the precursor preparation, on the composition and morphology of the solid decomposition products, were also studied. The gel combustion technique, using citric acid added to a mixture of 0.85Zn(NO₃)₂·6H₂O+0.15Cu(NO₃)₂·6H₂O, was applied in an attempt to obtain mixed Zn/Cu oxides of a particular mole ratio. The morphology of the solid decomposition products was examined by SEM.     

Polynitroethyl‐ and Fluorodinitroethyl Substituted Boron Esters

The reaction of boron oxide with various nitro‐substituted ethanols (2‐nitroethanol, 2‐fluoro‐2,2‐dinitroethanol, 2,2,2‐trinitroethanol) furnished the corresponding nitroethyl borates B(OCH₂CH₂NO₂)₃ ( 1 ), B(OCH₂CF(NO₂)₂)₃ ( 2 ), and B(OCH₂C(NO₂)₃)₃ ( 3 ). Fluorination of the anion [(NO₂)₂CCH₂OH]^? ( 4 ) resulted in 2‐fluoro‐2,2‐dinitroethanol ( 5 ), a precursor for 2 , and was thoroughly characterized. An interesting condensation was observed with the anion 4 to form the unusual dianion [(NO₂)₂CCH₂C(NO₂)₂]^2? ( 6 ). All compounds were fully characterized by multinuclear NMR spectroscopy, vibrational spectroscopy (IR, Raman), mass spectrometry and elemental analysis. The chemical, physical and energetic properties of 1 – 3 and 5 are reported, as well as quantum chemical calculations at the CBS‐4M level of theory to predict the enthalpies and energies of formation. X‐ray diffraction studies were performed, and the crystal structures for compounds 1 – 6 were determined and discussed thoroughly. The boron esters 1 – 3 are of interest as possible candidates for smoke‐free, green colorants in pyrotechnic applications, and in case of 2 and 3 also as promising high energy oxidizers.     

Synthesis,crystal structure,solid-state fluorescence,and interaction with DNA of mononuclear La(III) complex: La(Phen)2L2(NO3)

A mononuclear complex, La(Phen)₂L₂(NO₃) (Phen?=?1,10-phenanthroline, L?=?2-ethylphenylacetic acid), was synthesized by the reaction of La(NO₃)₃·H₂O, Phen and L at room temperature. The central ion shows 10-coordination with two Phen and two L molecules. Elemental analysis, IR spectra, and X-ray single-crystal diffraction were carried out to determine the composition and crystal structure. Solid fluorescence shows the luminescent properties of the complex. DNA-binding properties of the complex were examined by fluorescence spectra. The capability of cleavage of pBR322 DNA by the complex was investigated by agarose gel electrophoresis, showing cleaving efficiency.     

Complexes of Some Pyrido[1,2-a]pyrimidinium Perchlorates with Scandium,Yttrium, and Lanthanum. Crystal and Molecular Structure of 3-Chloro-9-Hydroxy-2,4-Dimethylpyrido[1,2-a]pyrimidinium Perchlorate

Complexes of scandium, yttrium, and lanthanum nitrates with 3-chloro-9-hydroxy-2,4-dimethylpyrido[1,2-a]pyrimidinium perchlorate (HL¹ClO₄) and 9-hydroxy-2,4-dimethylpyrido[1,2-a]pyrimidinium perchlorate (HL²ClO₄) were obtained. Their composition was formulated as Sc(LClO₄)₂(NO₃) and M(LClO₄)₂(NO₃)₂ (L = L¹ or L²; M = Y or La); structures for the complexes obtained were proposed. The crystal and molecular structure of HL¹ClO₄ was determined. Dissociation and complexation of HL¹ClO₄ and HL²ClO₄ in aqueous ethanol were studied using the spectroscopic method. Ligand dissociation and complexation constants were calculated. It was shown that a chlorine-containing organic ligand only slightly changes the composition and stability of the metal complexes.     

Reactions of nitrosyl chloride with [Ni(PPh3)2X2] (X=Cl,Br, NCS or NO3)

Summary Nitrosyl chloride has been treated with [Ni(PPh₃)₂X₂] (X = Cl, Br, NCS or NO₃) to obtain [Ni(PPh₃)XCl]₂ (X=Cl, Br, NCS or NO₃) and [Ni(OPPh₃)(SCN)Cl]₂. The compounds obtained were characterised by analyses, infrared (including far i.r.) and visible spectral studies, magnetic moment and conductivity measurements and many chemical reactions. It is proposed that the compounds have a dimeric structure with a distorted tetrahedral environment around the nickel atom and chloro-bridges.     

Interactions in the system Mn(NO<Subscript>3</Subscript>)<Subscript>2</Subscript>-HCONH<Subscript>2</Subscript>-H<Subscript>2</Subscript>O

Solubilities and solid phases in the system Mn(NO₃)₂-HCONH₂-H₂O were studied by an isothermal method at 25°C. The congruently saturating compound Mn(NO₃)₂ · 2HCONH₂ · 2H₂O was isolated; the concentration conditions for its crystallization in the system were determined. The solid phases of the system were characterized by physicochemical methods (X-ray powder diffraction, differential thermal analysis, IR spectroscopy, and crystal-optical analysis).     

Metal nitrate driven nitro Hunsdiecker reaction with α,β-unsaturated carboxylic acids under solvent-free conditions

Hunsdiecker reactions with α,β-unsaturated carboxylic acids were conducted under solvent-free conditions in the presence of a few drops of HNO₃ together with a variety of metal nitrates [Mg(NO₃)₂, Sr(NO₃)₂], Al(NO₃)₃, Ca(NO₃)₂, Ni(NO₃)₂, Cd(NO₃)₂, Zn(NO₃)₂, Hg(NO₃)₂, AgNO₃, ZrO(NO₃)₂, UO₂(NO₃)₂, Th(NO₃)₂] or ammonium nitrate. α,β-Unsaturated aromatic carboxylic acids underwent nitro decarboxylation to afford β-nitro styrenes in moderate to good yields, while α,β-unsaturated aliphatic carboxylic acids underwent decarboxylation to yield the corresponding nitro derivatives.     

Hydrothermal syntheses,structures and properties of three cyclic tetranuclear complexes and one 1D chain complex with 3,5-dinitrosalicylate

The hydrothermal reactions of Co(OAc)₂ · 4H₂O, 3,5-dinitrosalicylate (3,5-(NO₂)₂sal) and 2,2′-bipyridine (2,2′-bipy) with different reaction periods give metallamacrocycles 1 and 2 with the same chemical formula Co₄(2,2′-bipy)₄{3,5-(NO₂)₂sal}₄. Replacing Co(OAc)₂ · 4H₂O with Zn(NO₃)₂ · 6H₂O, using the same synthetic procedures, results in the formation of compound [Zn(2,2′-bipy){3,5-(NO₂)₂sal}]_n (3) with a 1D chain structure and the metallamacrocycle compound Zn₄(2,2′-bipy)₄{3,5-(NO₂)₂sal}₄ (4). Compounds 1 and 2 crystallize as two different polymorphs of cyclic tetranuclear compounds. Compounds 3 and 4 are polymorphic too. The compounds 1 and 4 are isomorphous. The weak coordination interactions have significant influence on the spacial orientations of the 3,5-(NO₂)₂sal ligand, and may affect the crystallization processes. There are antiferromagnetic interactions in the cyclic tetranuclear cobalt(II) compounds 1 and 2. Compound 3 exhibits weak fluorescent emission in the solid state at room temperature.     

Synthesis,Characterization, and Crystal Structures of Cu,Ag, and Pd Dinitramide Salts

The literature known, but not fully characterized, silver dinitramide transfer reagents AgN(NO₂)₂ ( 1 ), [Ag(NCCH₃)][N(NO₂)₂] ( 2 ), and [Ag(py)₂][N(NO₂)₂] ( 3 ) have been investigated by ¹⁰⁹Ag, ¹⁴N NMR and vibrational spectroscopy (IR, Raman). In addition, the poorly understood [Cu(NH₃)₄][N(NO₂)₂)]₂ ( 4 ) and [Pd(NH₃)₄][N(NO₂)₂]₂, ( 5 ) have also been prepared and characterized by ¹⁴N NMR and vibrational spectroscopy (IR, Raman). The structures of 2 — 5 have also been determined by X‐ray diffraction.     

Systeme ternaire: H2O-Zn(NO3)2-NH4NO3

The solid-liquid equilibria of the ternary system H₂O-Zn(NO₃)₂-NH₄NO₃ were studied by using a synthetic method based on conductivity measurements. Two isotherms were established at -25 and -20°C, and the stable solid phases which appear are: Ice, NH₄NO₃ , Zn(NO₃)₂·6H₂O and Zn(NO₃)₂·8H₂O Neither double salts, nor mixed crystals are observed at these temperatures and composition range. This revised version was published online in August 2006 with corrections to the Cover Date.     

On the preparation of nanosized Al2(WO4)3 by a precipitation method

Nanosized aluminum tungstate, Al₂(WO₄)₃, is prepared by a precipitation reaction between Na₂WO₄ and Al(NO₃)₃. The structure of the precipitated composition is determined by powder XRD analysis, IR and ²⁷Al MAS NMR spectroscopy. The thermal properties are examined by DSC, DTA and TG analyses combined with gas evolved analysis. Particle sizes and morphology are examined by TEM analysis. Precipitation reaction leads to the formation of an amorphous composition, which consists of dimer and trimer aluminum hydroxide species and WO₄^2? groups. Finely dispersed particles with dimensions of about 25 nm are formed. The precipitated composition is decomposed to amorphous Al₂(WO₄)₃ immediately after H₂O release. At 630 °C, amorphous Al₂(WO₄)₃ crystallizes in an orthorhombic modification of Al₂(WO₄)₃, the enthalpy of crystallization being 58 kJ/mol. The nanosized particles remain intact after the crystallization of amorphous Al₂(WO₄)₃. A significant particle growth take places when nanosized Al₂(WO₄)₃ is heated from 600 to 800 °C.     

Crystallization of interphase droplets in emulsion explosive matrices

The instability of emulsion explosive matrices is mainly due to the crystallization of interphases as oversaturated aqueous solutions of nitrate salts. The principal features of crystallization for this type of emulsion have been previously studied; however, there is no consensus regarding the mechanism of crystallization for an emulsion explosive matrix. This study is devoted to the investigation of the crystallization behavior of interphase droplets. By monitoring the mass change of emulsions during their aging process, it was found that the mass of the emulsions remains almost constant and that water still completely existed in the emulsion system after crystallization of the interphase droplets. The ammonium nitrate (NH₄NO₃) crystals in the emulsion explosive matrices were then separated successfully using a simple method. The thermal behavior of pure NH₄NO₃ and crystals in the emulsion explosive matrices was studied by differential scanning calorimetry-thermogravimetric analysis (DSC-TG) at a heating rate of 10?K/min. The experimental results show that the thermal behavior of the crystals in the emulsions was exactly the same as for pure NH₄NO₃, meaning that only NH₄NO₃ crystallized from the emulsion explosive matrices with no water crystals. Thus, it could be concluded that after crystallization of the dispersed drops in the emulsion explosive matrices, pure NH₄NO₃ crystals and new smaller droplets were produced.