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1.
Barium hydroxoaluminate hydrates were precipitated from different sodium hydroxoaluminate solutions at 20 °C; CAl varied from 0.1 to 0.5 M and initial Ba/Al2 ratios ( = excess OH/Al ratios) varied from 1 to 7. Precipitate compositions were determined by chemical analysis, infra-red spectrophotometry and thermal analysis. The compound BaO · Al2O3 · 7 H2O was precipitated at initial Ba/Al2 ratios of one to well above two while the compound 2 BaO · Al2O3 · 5 H2O was only precipitated over a narrow range of concentrations. The compound Ba(OH)2 · 8 H2O was precipitated from solutions of high hydroxide and barium ion concentrations. The ionic equilibria and precipitation mechanisms in different solutions are discussed.  相似文献   

2.
Magnesium hydroxoaluminate hydrates were precipitated from different sodium hydroxoaluminate and hydroxoaluminate-hydroxide solutions at ambient temperature, at CAl = 0.1 M, OH/Al ratios = 4–9 and XS OH/Al ratios = 1–6. The precipitations were monitored by potentiometric (pH) measurements while the final precipitate compositions were examined by chemical analysis, infra-red spectrophotometry and thermal analysis. At solution OH/Al ratio = 4, the main precipitate phase at 20°C was Mg(H2O)n[Al(OH)4]2 admixed with some Al(OH)3; at solution OH/Al ratio = 5, the main phase was Mg2(H2O)4[Al2(OH)10]; at solution OH/Al ratio = 7, the main phase was Mg4(H2O)n(OH)4[Al2(OH)10] while at solution OH/Al ratio = 9, the main phase was Mg6(H2O)n(OH)8[Al2(OH)10] admixed with some Mg(OH)2. These hydrates were dehydrated at 60–100°C probably to the compounds Mg2[Al2O3(OH)4], Mg4(OH)4[Al2O3(OH)4] and Mg6(OH)8[Al2O3(OH)4], respectively.  相似文献   

3.
Calcium aluminium hydroxides were coprecipitated from different mixed metal cation solutions — at total CM = 0.1 M and Ca/Al2 ratios from 1 to 4 — with sodium hydroxide solution at ambient temperature. The coprecipitations were monitored by potentiometric (pH) titration and the final coprecipitate compositions were examined by chemical analysis, infra-red spectrophotometry and thermal analysis Generally, microcrystalline aluminium hydroxide was first precipitated at pH about 4; this then redissolved on further addition of sodium hydroxide to form hydroxoaluminate anion and polyanion and calcium aluminium hydroxide coprecipitates were formed continuously at pHs from about 9 to above 12. Their compositions were similar to the calcium hydroxoaluminate hydrates formed by direct precipitation from high pH sodium hydroxoaluminate solutions. At Ca/Al2 ratio = 1, the main phase was probably Ca2(H2O)h[Al2(OH)4]2 with some Al(OH)3; At Ca/Al2 ratio = 2, the main phase was probably Ca2(H2O)h[Al2(OH)10] dehydrating to Ca2[Al2O(OH)8]; At Ca/Al2 ratios = 3–4, the main phase was Ca2(H2O)h[Al2(OH)10] with increasing amounts of Ca4(H2O)h(OH)4[Al2(OH)10] and 5–10 percent adsorbed or post-precipitated Ca(OH)2.  相似文献   

4.
Zine aluminium hydroxides were coprecipitated from different mixed metal cation solutions, at CM tot = 0.1 M and at Zn/Al2 ratios from 1 to 4, with sodium hydroxide solution. The coprecipitations were monitored by potentiometrie (pH) titration and the final coprecipitate compositions were examined by chemical analysis, infra-red spectrophotometry and thermal analysis. Generally, microcrystalline aluminium hydroxide was first precipitated at pH about 4; this then partially redissolved on further addition of sodium hydroxide (to form hydroxoaluminate anion) and zinc aluminium hydroxide coprecipitates were formed continuously at pHs from 5.5–6 to above 9. Their compositions were similar to the magnesium hydroxoaluminate coprecipitated from magnesium aluminium solutions. At Zn/Al2 ratio = 1, the main phase was probably Zn(H2O)n [Al(OH)4]2; at Zn/Al2 ratio = 2, the main phase was probably Zn2(H2O)n [Al2(OH)10], whereas at Zn/Al2 ratio = 4, the main phase was probably Zn(H2O)n(OH)4[Al2(OH)10].  相似文献   

5.
Magnesium hydroxoaluminate hydrates were coprecipitated from different mixed metal cation solutions at Mg/Al2 ratios from 1 to 4 by ammonium hydroxide. The coprecipitations were monitored by potentiometric titration and the final precipitate compositions were examined by chemical analysis, X-ray diffraction, infra-red spectrophotometry and thermal analysis. The process of coprecipitation was similar to that for coprecipitation with sodium hydroxide but large excess of ammonium hydroxide was required for complete reaction at pHs from about 8 to 10.
  • At Mg/Al2 = 1, the main phase was probably Mg(H2O)h [Al(OH)4]2;
  • at Mg/Al2 = 2, the main phase was probably Mg2(H2O)h [Al2(OH)10];
  • at Mg/Al2 = 4, the main phase was probably (MgOH4) (H2O)h [Al2(OH)10].
  相似文献   

6.
We examined the solid-state water-soluble amorphous precursors that are formed by partial thermal decomposition of Al(NO3)3·9H2O (aluminum nitrate nonahydrate: ANN) using Raman and FTIR and solid-state magic-angle spinning NMR spectroscopy. We also studied the species formed in the aqueous alumosols formed by dissolution of the pre-ceramic precursors using 27Al NMR spectroscopy. Species identified in the alumosols included the Al3+(H2O)6 monomer, the [AlO4Al12(OH)24(H2O)12]7+(Al13) Keggin ion, and the Al30 polycation, [Al30O8(OH)56(H2O)24]18+, as well as various other oligomers or nanoparticles containing IV-, V- and VI-coordinated Al3+ ions.  相似文献   

7.
We have synthesized a multi-ligand chelate copper(II) complex [Cu · (C7H5O3] · (C12H8N2) · H2O1 · (C7H6O3)· NO3, and determined its structure by X-ray diffraction method. The space group of the title compound is P21/a. It is monoclinic, with a = 14.227(4), b = 9.627(4), c = 19.008(7) Å, β = 102.06(3)·, Z = 4. The two salicyclic acid molecules in the cell are in different environments, one inner, the other outer. The geometry around Cu(II) is a four-coordinated distorted plane square. The two coordinating atoms are two nitrogen atoms from phenanthroline, one oxygen atom from salicyclic acid, one oxygen atom from water.  相似文献   

8.
Abstract  The adduct of di-triethylammonium, tetrachlorobenzene-1,4-dicarboxylate and tetrachlorobenzene-1,4-dicarboxylic acid, i.e. {2(C2H5)3NH+ C8Cl4O42− H2C8Cl4O4}, crystallizes in triclinic, P-1 with cell dimensions of a = 8.5080(5) ?, b = 8.9789(6) ?, c = 12.5212(8) ?, α = 93.301(1)°, β = 109.107(1)°, γ = 103.565(1)°, V = 869.2(1) ?3 and Z = 2. The C8Cl4O42− and H2C8Cl4O4 moieties link with each other by O–H···O along c axis, C–Cl···O=C along b axis and C–Cl···Cl–C along a axis to form the 3D framework of the crystal structure. The (C2H5)3NH+ cations reside in the cavities of the 3D framework via various intermolecular interactions such as N–H···O, C–H···O and C–H···π. Index Abstract  In the title compound, tetrachlorobenzene-1,4-dicarboxylates and tetrachlorobenzene-1,4-dicarboxylic acids form 3D framework by hydrogen bonds and halogen bonds, and triethylammoniums reside in the voids of the framework via supramolecular interactions .  相似文献   

9.
The hydrothermal reaction of a mixture of VOSO4 · xH2O, 1,2,4,5-benzenetetracarboxylic acid (pyromellitic acid) and 0.1 M H2SO4 for 72 h at 160 °C gives blue needle like crystals of [VIV 2O2(H2O)2(C6H2(COO)4)] in 30% yield. The compound has a porous 3-D extended network structure having a rigid architecture which is held together by the multidentate functionalities of 1,2,4,5-benzenetetracarboxylate ligand. Crystal data for the compound: monoclinic space group C 2/c (No:15), a = 11.756(5) ?, b = 9.645(3) ?, c = 11.822(7) ?, β = 107.10(4)°, Z = 8. The compound constitutes the first example of a fully reduced oxovanadium based solid incorporating the organic ligand. This article consists of synthesis, crystal structure and characterization of [VIV 2O2(H2O)2(C6H2(COO)4)].  相似文献   

10.
The precipitation of barium, strontium, calcium and magnesium polymetaphosphate hydrates was studied from aqueous solutions of initial metal salt concentrations from 0.001 to 3 M at 20 °C; equivalent sodium polymetaphosphate solutions were added to the alkaline-earth metal chloride solutions. Precipitate compositions were determined by chemical analysis, paper chromatography, potentiometric analysis, thermogravimetric and differential thermal analysis and infra-red spectrophotometry; final crystallite morphologies and sizes were studied by scanning electron microscopy and X-ray powder diffraction. Nucleation rates and nucleus numbers (at the end of the induction periods) were very high; crystal numbers varied from 1014 to 1015 at the critical concentrations to above 1017 per 1. solution. Crystal growth rates were also very high and varied as the fourth power of the initial metal salt concentration. High molecular-weight metal polymetaphosphate hydrates were precipitated from the more dilute solutions (0.001 to 0.025 M) while increasing amounts of the more soluble intermediate and low molecular-weight products were precipitated from the more concentrated solutions. Washing with cold water removed the tri- and tetralinear and cyclic phosphate products. The magnesium salts were not precipitated even from 3 M aqueous solutions. The precipitates from aqueous (NaPO3(I))n (n = 12) solutions had the compositions (BaP2O6 · 2.5 H2O)6, (SrP2O6 · 3 H2O)n and (CaP2O6 · 4 H2O)n while the magnesium salt precipitate from 20 percent aqueous acetone solution had the composition (MgP2O6 · 4 H2O)n, the precipitate n values varied from 19 to 13. The precipitates from aqueous (NaPO3(II))n (n = 20) solutions contained 0.5n to n additional adsorbed water molecules; these precipitate n values varied in turn from 40 to 26. The final precipitate powders consisted of ‘spherules’ of highly microcrystalline or amorphous polymer glass; the spherule diameters were about 0.2 μm at the critical concentrations and decreased to below 0.05 μm with increasing solution concentrations.  相似文献   

11.
The structure of the title compound (C9H13NO2NaP · 3 H2O) (Toldimfos Na · 3 H2O) has been determined at room temperature. The crystals are monoclinic, a = 38.15(2) Å, b = 4.940(3) Å, c = 14.510(8) Å, β = 109.58(4)°, V = 2576(3) Å3, Z = 8, Dcalc = 1.419 g cm—3, space group C2/c. The structure was solved by direct methods and refined by full-matrix least-squares method (MoKα radiation; R = 0.061). Indexed powder diffraction pattern for the drug is also reported.  相似文献   

12.
Abstract  The mononuclear complex [Na(C7H6O4)(H2O)3](C7H5O4) · 2H2O has been synthesized and characterized by IR, single crystal X-ray and thermal analysis. The compound crystallizes in the monoclinic space group P21 with a = 3.623(2) ?, b = 15.872(6) ?, c = 15.650(5) ?, β = 93.13(4)°, V = 896.6(7) ?3 and Z = 2. The central sodium ion is six coordinated with distorted octahedral geometry by two oxygen atoms from two bridging 3,5-dihydroxybenzoate ligands and four ones from different water molecules. The notable feature of the title complex is the formation of a three-dimensional network, through the combination of coordination bonds, hydrogen bonds and π···π interactions. There are one-dimensional channels in the structure, filled in by water molecules. The compound dehydrates in the temperature range of 70–125 °C and then is stable up to 230 °C. Index Abstract  The mononuclear complex [Na(C7H6O4)(H2O)3](C7H5O4) · 2H2O has been synthesized and characterized by IR, single crystal X-ray and thermal analysis.   相似文献   

13.
The structure of a new modification of the barium pentaborate β-Ba[B5O8(OH)] · H2O synthesized under hydrothermal conditions is investigated. This structure differs from the previously studied structure of the α-Ba[B5O8(OH)] · H2O compound by a shorter interlayer spacing and a higher degree of filling of the intersheet space with water molecules and barium atoms (the space group P is retained). The structure of the Ba2[B5O9] Cl · 0.5H2O pentaborate from the family of orthorhombic hilgardites (space group Pnn2) is refined, and the property of this crystal to generate the second optical harmonic is revealed. It is found that the previously studied pentaborate Ba5[B20O33(OH)4]H2O exhibits a nonlinear optical activity. The relationship between the structure and properties of hydrous and anhydrous pentaborates is discussed. Original Russian Text ? E.L. Belokoneva, S.Yu. Stefanovich, M.A. Erilov, O.V. Dimitrova, N.N. Mochenova, 2008, published in Kristallografiya, 2008, Vol. 53, No. 2, pp. 255–263.  相似文献   

14.
Zinc aluminium hydroxide hydrates were coprecipitated from different mixed cation solutions at Zn/Al2 ratios from 1/2 to 4/1. The coprecipitations were monitored by potentiometric titrations and the final coprecipitate compositions were examined by chemical analysis and atomic absorption spectrophotometry, X-ray diffraction and preliminary thermal analysis. The product from Zn/Al2 = 1/2 solution was amorphous: at Zn/Al2 = 1/1.5, the main phase (after drying at 95 °C) was a zinc hydroxoaluminate Zn[Al(OH)4]2 together with some gibbsite: at Zn/Al2 = 1, the main phase was probably a solid solution (of Zn[Al(OH)4]2 with Zn2[Al2(OH)10]) together with Zn2[Al2(OH)10]: at Zn/Al2 = 2, the main phase was a mixture of Zn2[Al2(OH)10] with (ZnOH)4 [Al2(OH)10] and some gibbsite: at Zn/Al2 = 4, the main phase was (ZnOH)4 [Al2(OH)10] with some zinc hydroxide.  相似文献   

15.
The growing of single crystals of calcium aluminates of compositions 12 CaO · 7 Al2O2, CaO · Al2O3, and CaO · 2 Al2O3 by zone melting under vacuum of 10−5 mm Hg permitted to establish that some of the Al3+ ions in octahedral coordination have been driven back by the moving crystallization front. Energetically, this process can be represented on the basis of the viscous flow model with the activation energy of −45 kcal/mole. The possible mathematical models have been considered for the processes of preparation of single phase crystals of the aluminates mentioned above which take account of incongruent vaporization of the component oxides and refining of the melt from structural impurities by the moving crystallization front.  相似文献   

16.
The molecular structure of the title compound, C14H11ClN2O4, was determined by single crystal X-ray diffraction. The compound crystallizes in the monoclinic sp. gr. P21/c with Z = 4. The title compound, C14H11ClN2O4, is a Schiff base which adopts the phenol-imine tautomeric form in the solid state.The molecule is almost planar and the dihedral angle between the planes of two aromatic ring is 2.2(1)°. The molecular structure is stabilized by intramolecular O–H···N hydrogen bond which generates a six-membered ring. In the crystal structure, the molecules are linked together by intermolecular C–H···O interactions.  相似文献   

17.
Magnesium aluminium hydroxocarbonate hydrates were coprecipitated from mixed metal nitrate solutions, at total CM = 0.2 M and Mg/Al2 = 1 ratio, with four sodium hydrogen carbonate-sodium carbonate solutions (of pH 8.1 to 11.5) at ambient temperature. The course of precipitation was monitored by potentiometric (pH) titration, and the compositions of the primary and final precipitates were determined by chemical analysis, infrared spectrophotometry and X-ray diffraction. Precipitation generally occurred through three stages, primary precipitation (of low CO3 aluminium hydroxocarbonates) at low pH with evolution of carbon dioxide, their dissolution by complexing to form hydroxocarbonatoaluminate anions and then secondary precipitation of the final coprecipitate at higher pHs. The final product from coprecipitation by sodium hydrogen carbonate solution (pH 8.1) was mainly the magnesium hydroxocarbonatoaluminate ‘MAHC I’; the final products from coprecipitation by sodium hydrogen carbonate-sodium carbonate solutions (pH 9.4 and 10.3) were ‘MAHC I’/‘MAHC II’ mixture and ‘MAHC II’/‘MAHC I’ mixture whereas the final product from coprecipitation by sodium carbonate solution (pH 11.5) was a complex mixture if ‘MAHC II’ with ‘MAHC I’ and ‘MAHC III’;
  • ‘MAHC I’ was probably Mg2[Al4(OH)10(CO3)3] · hH2O,
  • ‘MAHC II’ was probably Mg[Al2(OH)4(CO3)2] · h H2O whereas
  • ‘MAHC III’ was probably Mg[Al2(OH)6CO3] · h H2O.
  相似文献   

18.
A new hexaborate, Ba0.975[B6O9(OH)(O0.975Br0.025) · B2O(OH)3], was synthesized under hydrothermal conditions. This compound is structurally similar to tunnelite and the synthetic borates Pb[B6O10(OH) · B2O(OH)3], Pr[B6O10(OH) · B2O(OH)4], and Nd[B6O10 · B3O3(OH)4] · H2O studied earlier. In the new hexaborate and the refined pentaborate Ba2[B5O8(OH)2]OH, in which the polyanions adopt an orientation in layers unusual for pentaborates, thermal vibrations of the terminal groups were revealed. This fact reflects the real crystal structure. The nonlinear optical properties of the crystals of the polar pentaborate Na4Ba4[B20O34(OH)4] were determined. The crystal structure of the related pentaborate Ba5[B20O33(OH)4]H2O was considered. The factors most likely responsible for the difference in the second-harmonic generation signal for this pair were revealed.  相似文献   

19.
The compound 2-ureido-pentanedioic acid was synthesized and characterized by FT-IR and NMR spectra. Its molecular structure was solved by single crystal X-ray diffraction. In the title compound, C6H10N2O5, the chiral structure is stabilized by intermolecular O–H···O and N–H···O hydrogen bonds in a supramolecular assembly formed by infinite chains parallel to the bc plane with graph set C(4) connected by amide-acid dimers R22(8) into a three-dimensional network.  相似文献   

20.
(C3H5N2)2[Cd(C3H4N2)2Nb2O3F8]·2H2O (C3H4N2=imidazole) (1) was prepared from the hydrothermal reaction of Nb2O5, 3CdSO4·8H2O, C3H4N2, HF and H2O at 403 K, and characterized by single crystal X-ray diffraction and IR spectra. 1 crystallizes in the orthorhombic system, space group Pba2, with a=11.0192(9), b=16.8012(14), c=6.8717(6) ?, and Z=2. The crystal is made up of [Cd(C3H4N2)2Nb2O3F8]2− anions, [C3H5N2]+ complex cations and H2O molecules of crystallization. And the backbone of the compound is a one dimension coordination polymeric chain containing the anions. The complex cations and anions are linked through hydrogen bonding interactions. Co-crystallized water molecules fill in the pores and hydrogen bond to the host. Bond valence sums show that O1, O3 and F3 have much more negative charge, which are in agreement with the crystal structure that they act as bridging atoms.Supplementary material CCDC-606794 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge at http://www.ccdc.cam.ac.uk/ const/retrieving.html or from the Cambridge Data Centre (CCDC), 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44(0)1223-336033 or e-mail: deposit@ccdc.cam.ac.uk.  相似文献   

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