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1.
Coordination equilibria in the Co(II)–Ni(II)–2-aminopropanoic acid (HAla)–EDTA system have been studied spectrophotometrically at different molar ratios of the reagents in a wide pH range. It has been found that, when metal ions are in excess with respect to EDTA at pH 5–9, polyheteronuclear complexonates [(CoAla)Edta(NiAla)]2–, [(CoAla2)Edta(NiAla2)]4–, [(NiAla2)Edta(CoAla2)2]4–, [(CoAla2)Edta(NiAla2)2]4–, and [(NiAla2)2Edta(CoAla2)2]4– form in a solution. The equilibrium constants of formation of these complexes and their overall stability constants have been calculated. Possible structures of the polynuclear complexonates are discussed.  相似文献   

2.
Pourbaix diagrams of Cu–H2SO4–H2O and Ni–H2SO4–H2O systems have been refined, and stability regions of the sulfite phases have been determined. State diagrams of double copper(I)–copper(II) and copper(I)–nickel(II) sulfites have been constructed. Double copper(I)–nickel(II) sulfite has been isolated from aqueous solutions saturated with sulfur dioxide. The solutions at different ratios of the metals have been studied by spectrophotometry; the isolated double sulfite has been studied by X-ray diffraction, IR spectroscopy, dispersion analysis, and thermal analysis. Fundamentals of thermodynamic prognostication of the Cu2SO3·MSO3 double sulfites synthesis have been elaborated.  相似文献   

3.
Relationships between synthesis conditions, phase composition, and ion-exchange properties have been analyzed on the basis of results of physicochemical study for reaction products in the (NH4)2TiO(SO4)2–H3PO4–H2O system. Mechanisms have been suggested for the formation of final titanium phosphate phase in different synthesis methods.  相似文献   

4.
The specifics of preparation of chromium double pyrophosphates in systems Cr(NO3)3–Na4P2O7–H2O, CrCl3–Na4P2O7–C2O, and KCr(SO4)2–Na4P2O7–H2O are discussed. Changes in pH of the mentioned systems have been studied depending of the component ratio. The effects of the deposition duration and sodium pyrophosphate concentration on pH have been studied for system Cr(NO3)3–Na4P2O7–H2O. Phase composition has been determined for compounds prepared in systems Cr(NO3)3–Na4P2O7–H2O and KCr(SO4)2–Na4P2O7–H2O. It has been found that the acid residue anions do not substantially affect the formation of a continuous series of compounds consisting of hydroxy and hydro combinations of chromium ions and pyrophosphate ion, whereas cations can have an effect. System KCr(SO4)2–Na4P2O7–C2O is less sensitive to reaction conditions than systems in which normal salts Cr(NO3)3 and CrCl3 act as a source of Cr3+ cation. A product stable over time can be prepared in system KCr(SO4)2–Na4P2O7–C2O; after heat treatment at 900°C, it is a mixture of KCrP2O7 and a-CrPO4 phases.  相似文献   

5.
Efficient methods for the preparation of trichloro- and tribromo(2-ethoxyalkyl)-λ4-tellanes in 80 to 100% yield have been developed on the basis of ethoxytelluration of hex-1-ene, hept-1-ene, and oct-1-ene with tellurium tetrahalides. Tribromo(2-ethoxyalkyl)-λ4-tellanes have been reduced to 1,2-bis(2-ethoxyalkyl)ditellanes in 92–95% yield with the system NaBH4–H2O–THF.  相似文献   

6.
A phase equilibria diagram of the partial system NdPO4–K3PO4–KPO3 has been developed as part of the research aimed at determining the phase equilibrium relationships in the oxide system Nd2O3–K2O–P2O5. The investigations were conducted using thermoanalytical techniques, X-ray powder diffraction analysis and reflected-light microscopy. Three isopleths existing between: K3Nd(PO4)2–K4P2O7, NdPO4–K5P3O10 and NdPO4–K4P2O7 have been identified in the partial NdPO4–K3PO4–KPO3 system. Previously unknown potassium-neodymium phosphate “K4Nd2P4O15” has been discovered in the latter isopleth section. This phosphate exists in the solid phase up to a temperature of 890 °C at which it decomposes into the parent phosphates NdPO4 and K4P2O7. Four invariant points: two quasi-ternary eutectics, E1 (1057 °C) and E2 (580 °C) and two quasi-ternary peritectics, P1 (1078 °C) and P2 (610 °C), occur in the NdPO4–K3PO4–KPO3 region.  相似文献   

7.
The System Ammonium Nitrate–Monoammonium Phosphate–Urea Nitrate–Urea Phosphate–Water The 20 and 40°C isotherms of the quaternary system ammonium nitrate– monoammonium phosphate–urea nitrate–urea phosphate–water have been determined by an analytical method. NH4H2PO4 and CO(NH2)2·HNO3 form a stable ternary system at both temperatures.  相似文献   

8.
[Hg2(L1)2I4] (1), [Cd2(L1)2I4] (2), {[Cd(L1)2(SO4)(H2O)]·4H2O}n (3), {[Zn2(L2)2(Cl)4]·0.5H2O} (4), {[Cu2(L2)2(SO4)2(H2O)4]·2.5H2O} (5), and {[Cd(L2)2(SO4)(H2O)]·3H2O}n (6), based on N–(3–picolyl)–N′–(3–pyridyl)urea (L1) or N–(4–picolyl)–N′–(3–pyridyl)urea (L2), have been synthesized and characterized by elemental analyses, IR spectra, single-crystal and powder X-ray diffraction, and thermogravimetric analyses. Complexes 1 and 2 are isomorphous and feature similar rectangular metal organic loops, which were further extended into 2-D supramolecular structures through hydrogen bonds. Complex 3 possesses a 2-D sql sheet, and the channels between the neighboring sheets are filled with lattice water molecules, which formed a 1-D water tape. Complex 4 also exhibits a rectangular metal organic loop and a 3-D supramolecular structure with the help of hydrogen bonding interactions. Complex 5 also possesses a metal organic loop, and the water molecules interacted with sulfates, constructing a 1-D water–sulfate tube. Complex 6 features a 1-D loop polymeric chain. Moreover, the solid state luminescences of 14 and 6 have been investigated.  相似文献   

9.
The enthalpy of solution of LаОНMoO4 and Cs2MoO4 in aqueous HCl at 298 К has been determined by solution calorimetry, and the standard enthalpy of formation of lanthanum hydroxomolybdate has been calculated. The enthalpies of solution of NaLa(MoO4)2 and Na5Lа(MoO4)4 in molybdate melt at 973 K have been determined by high-temperature melt solution microcalorimetry, and the high-temperature enthalpies of the double molybdates in the 298–1000 K range have been measured by the mixing method. The standard enthalpies of formation of the double molybdates have been calculated using data available from the literature. The low-temperature heat capacity of NaLa(MoO4)2 in the 60–300 K range has been measured on an adiabatic vacuum calorimeter. The basic thermodynamic properties of NaLa(MoO4)2, Na5Lа(MoO4)4, and LаОНMoO4 have been calculated.  相似文献   

10.
Ternary eutectic of the NH4NO3–NH4Cl–H2O system at–23.6°С has been found using a set of theoretical and experimental methods. According to the data of visual-polythermal and differential thermal analyses data, crystallization surface of the system has been plotted at–23.6 to 100°С.  相似文献   

11.
A facile and efficient strategy for the synthesis of hierarchical yolk–shell microspheres with magnetic Fe3O4 cores and dielectric TiO2 shells has been developed. Various Fe3O4@TiO2 yolk–shell microspheres with different core sizes, interstitial void volumes, and shell thicknesses have been successfully synthesized by controlling the synthetic parameters. Moreover, the microwave absorption properties of these yolk–shell microspheres, such as the complex permittivity and permeability, were investigated. The electromagnetic data demonstrate that the as‐synthesized Fe3O4@TiO2 yolk–shell microspheres exhibit significantly enhanced microwave absorption properties compared with pure Fe3O4 and our previously reported Fe3O4@TiO2 core–shell microspheres, which may result from the unique yolk–shell structure with a large surface area and high porosity, as well as synergistic effects between the functional Fe3O4 cores and TiO2 shells.  相似文献   

12.
《Mendeleev Communications》2022,32(3):405-407
The flammability limits of stoichiometric mixtures (20–80% H2 + 80–20% CH4) + O2 over Rh and Pd were determined in the pressure range 0–200 Torr and the temperature range 200–500 °C. It has been shown that the dark reaction in the mixture (80% H2 + 20% C4H8)stoich + O2 leads to the formation of carbon nanotubes with a mean diameter of 10–100 nm.  相似文献   

13.
The Schiff base, 2–salicylidene–4–aminophenyl benzimidazole in ethanol undergoes activation of –N=CH– bond by Ni2+ in the presence of ammonia or primary alkyl amine to produce nickel complexes of the formula Ni{o–C6H4(O)CH NR}2 . n H2O [R = H, Me; n = 0; R = Et, n = 0.5] and 4–aminophenyl benzimidazole. The products have been identified by elemental analysis, magnetic susceptibility measurements and IR, ESR, mass and extensive NMR spectral studies. The possible mechanism for the activation of –N=CH – bond has also been proposed. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

14.
The polymerizations of 4-methyl-1-pentene(4M1P), 4-methyl-2-pentene (4M2P), 2-methyl-2-pentene (2M2P), and 2-methyl-1-pentene (2M1P) with Ziegler-Natta catalyst have been investigated. Both 4M1P and 4M2P were found to polymerize with TiCl3–(C2H5)Al catalyst to give high molecular weight poly(4M1P), while 2M2P and 2M1P did not give polymers with 4M1P units. However, when the polymerizations of 2M1P and 2M2P were carried out with ternary catalyst systems, TiCl3–(C2H5)AlCl–(PPh3)2PdCl2 and TiCl3–(C2H5)AlCl–Ni(SCN)2 polymers with 4M1P units were obtained in low yield. It was concluded that these four methylpentenes could polymerize with the monomer-isomerization polymerization mechanism to poly(4M1P). The results of the observed isomer distribution of methylpentenes recovered, and the rate of polymerization of four methylpentenes suggest that the isomerization from 2M1P to 4M1P with the above ternary catalyst systems might proceed via a direct one-step isomerization mechanism.  相似文献   

15.
The first organic amine‐templated holmium sulfate [C2N2H10]3[Ho2(SO4)6·2H2O] ( 1 ) has been synthesized solvothermally and has been structurally characterized by single‐crystal X‐ray diffraction studies, IR spectroscopic, thermogravimetric (TG) and inductivity coupled plasma (ICP) measurements. Crystal analyses of compound 1 showed a novel inorganic layer constructed from the zigzag and helical [–Ho–O–S–O–]n chains, both of the chains are connected by μ‐2 SO42– groups to form 10‐membered rings. The solvent plays an important role during the formation of 1 .  相似文献   

16.
Products of the zirconium powder reaction with amorphous boron in a Na2B4O7 ionic melt at 650–850°C and those of the ZrCl4 reaction with NaBH4 at 300–725°C have been studied by means of X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, thermogravimetry, and elemental analysis. At temperature ≥750°C, single-phase ZrB2 with the particle size of 60–80 nm is formed in a Na2B4O7 ionic melt, whereas the ZrB2 powder obtained via the reaction of ZrCl4 with NaBH4 at temperature ≥575°C consists of particles differing in the shape, some of which are close to spherical with diameter of 10–35 nm.  相似文献   

17.
The reduction of R*–SiBr2–SiBr2–R* ( 2 ) with NaR* (R* = supersilyl = SitBu3) in presence of C2H4 provides a white crystalline solid (η2‐C2H4)R*Si–SiR*(Br)(CH2–CH2–R*) ( 3 ) characterized by X‐ray diffraction analysis. Compound 3 is accompanied with an impurity of R*(Br)2Si–Si(Br)(R*)(CH2–CH2–R*) ( 4 ). The formation of 3 and 4 runs complicated because of several reactive partners. However, reduction of 2 with sodium naphthalenide in presence of ethene runs straightforward with formation of a mixture of tetrahedrane R*4Si4 ( 1 ) and bis(silirane) R*(η2‐C2H4)Si–Si(η2‐C2H4)R* ( 5 ). The latter is formed by [1+2]‐cycloaddition reaction of intermediate disilyne R*Si≡SiR* with ethene. Compound 5 has been characterized by X‐ray structure determination. The 1H NMR spectrum of the silacyclopropane ring protons shows AA′BB′ complex spectrum comprising of 2 sets each of 12 transitions.  相似文献   

18.
Halide Ions as Catalyst: Metalcentered C–C Bond Formation Proceeded from Acetonitril AlMe3 reacts at 20 ?C in acetonitrile to the complex [Me3Al(NCMe)] ( 1 ). By addition of cesium halides (X = F, Cl, Br) a trimerisation to the heterocycle [Me2Al{HNC(Me)}2C(CN)] ( 2 ) has been observed. The reaction might be carried out under catalytic conditions (1–2 mol% CsX). The gallium complex [Me2Ga{HNC(Me)}2 · C(CN)] ( 3 ), generated under similar reaction conditions, can be converted to the silylated compound [Me2Ga{Me3SiNC(Me)}2C(CN)] ( 4 ) by successive treatment with two equivalents n‐butyllithium and Me3SiCl. 3 reacts under hydrolysis conditions (1 M hydrochloric acid) to the iminium salt [{H2NC(Me)}2C(CN)]Cl ( 5 ). A mixture of H2O, Ph2PCl and 3 in THF/toluene leads in a unusual conversion to the diphospane derivative [Ph2P–P(O)(Me2GaCl)] ( 6 ). 1 , 2 , 4 , 5 and 6 have been characterized by NMR, IR and MS techniques. X‐ray structure analyses were performed with 1 , 2 , 4 and 6 · 0.5 toluene. According this 1 possesses an almost linear axis AlNCC [Al1–N1–C3: 179,5(2)?; N1–C3–C4: 179,7(4)?]. 2 is an AlN2C3 six‐membered heterocycle with two iminium fuctions. One N–H group is responsible for a intermolecular chain‐formation through hydrogen bridges to an adjacent nitrile group along the direction [010]. The basic structural motif of the heterocycle 3 has been maintained after silylation to 4 . In 6 · 0.5 toluene an unit Me2GaCl, originated from 3 , is coordinated to the oxygen atom of the diphosphane oxide Ph2P–P(O)Ph2.  相似文献   

19.
The interaction in the GeCl4–nicotinoyl(isonicotinoyl, 2-, or 4-aminobenzoyl) hydrazone of 2-hydroxybenz(2-hydroxy-1-naphth)aldehyde (H2L)–CoCl2–methanol systems has resulted in the formation of [Ge(L·H)2][CoCl4nCH3OH complexes with germanium chelates [Ge(L·H)2]2+ protonated at the exo chelate nitrogen atom (NPy or NH2) as the cation. The type of electrolytic dissociation and character of thermolysis of the complexes have been revealed. Spectral, thermal, and magnetic properties of the complexes have been studied.  相似文献   

20.
Chelates formation of Fe(III) with 7–hydroxy–4–methyl coumarin–6–carboxylic acid (HMCCH)2 and 8–amino–7–hydroxy–4–methyl coumarin (AHMCH) have been studied. It has been observed that Fe(III) forms 1:2 (metal:ligand) chelates with HMCCH2 and AHMCH. The stability constants of these chelates at different ionic strengths and the effect of temperature on the stability constants of these chelates have been studied. The thermodynamic parameters such as entropy change (ΔS), free energy of formation (ΔG) and enthalpy change (ΔH) have also been calculated. The effect of dielectric constant oh the stability constants of these chelates have been studied. Estimation of nanogram quantities of Fe(III) with these ligands and the effect of diverse ions have also been studied and the results have been compared with other methods used for estimation of Fe(III).  相似文献   

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