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1.
The RbCl · MgCl2 · 6H2O? NH4Cl · MgCl2 · 6H2O? H2O and CsCl · MgCl2 · 6H2O? NH4Cl · MgCl2 · 6H2O? H2O systems have been investigated at 50°C. The formation of continuous series of mixed crystals is observed. An almost complete coincidence of the distribution coefficients values of the components between the solid and liquid phases determined experimentally and calculated theoretically using only solubility data for the two double salts has been established. The 2 RbCl · CoCl2 · 2H2O? RbCl · MgCl2 · 6H2O? H2O system has been studied at 25°C. It has been established that this system belongs to the simple eutonic type. The two double salts form no mixed crystals between each other. This fact is explained by the different character of the metal-ligand interaction of Mg2+ and Co2+ ions in aqueous halide systems.  相似文献   

2.
2CaO·3B2O3·H2O which has non-linear optical (NLO) property was synthesized under hydrothermal condition and identified by XRD, FTIR and TG as well as by chemical analysis. The molar enthalpy of solution of 2CaO·3B2O3·H2O in HCl·54.572H2O was determined. From a combination of this result with measured enthalpies of solution of H3BO3 in HCl·54.501H2O and of CaO in (HCl+H3BO3) solution, together with the standard molar enthalpies of formation of CaO(s), H3BO3(s), and H2O(l), the standard molar enthalpy of formation of −(5733.7±5.2) kJ mol−1 of 2CaO·3B2O3·H2O was obtained. Thermodynamic properties of this compound were also calculated by a group contribution method.  相似文献   

3.
The three-component systems RbClMnCl2H2O, 2RbCl · CoCl2 · 2H2O2RbCl · CuCl2 · 2H2OH2O, 2RbCl · CoCl2 · 2H2O2RbCl · MnCl2 · 2H2OH2O have been studied at 25°C. In the 2RbCl · CoCl2 · 2H2O2RbCl · CuCl2 · 2H2OH2O system, a discontinuous series of mixed crystals is formed and in the 2RbCl · CoCl2 · 2H2O2RbCl · MnCl2 · 2H2OH2O system, a continuous series is present.The unit cell parameters of the 2RbCl · CoCl2 · 2H2O double salt were determined: a = 5.586(2) Å, b = 6.469(3) Å, c = 6.988(2) Å, α = 65.31(3)°, β = 87.69(3)°, γ = 84.65(4)°, volume 228.4 Å3, Z = 1.The results obtained and discussed in conjunction with the crystal structure data suggest that for 2MICl · MIICl2 · 2H2O type salts the triclinic structure is stable only when the large rubidium and cesium ions participate in combinations with non-Jahn-Teller metal(II) ions. In the cases of Jahn-Teller metal(II) ions or with potassium or ammonium ions a tetragonal structure is always stable.  相似文献   

4.
Solubility of the quaternary system RbCl-EuCl3-HCl(13.44, 22.75%)-H2O at 298.15 K was determined and corresponding equilibrium diagrams were constructed. The quaternary system is simple, and consists of two equilibrium solid phases RbCl and EuCl3 · 6H2O. The composition of double saturation point (average) is 13.29% HCl, 16.18% RbCl, and 18.72% EuCl3 for the RbCl-EuCl3-HCl(13.44%)-H2O quaternary system, and 22.44% HCl, 15.59% RbCl, and 6.26% EuCl3 for the RbCl-EuCl3-HCl (22.75%)-H2O quaternary system.  相似文献   

5.
刘志宏  赵莉  胡满成 《中国化学》2003,21(12):1569-1572
Introduction   2MgO·B2 O3(Mg2 B2 O5)and 2MgO·B2 O3·H2 Omightbepreparedaswhiskermaterials .12MgO·B2 O3·H2 OnamedszaibelyiteisamagnesiumboratemineralwithastructuralformulaofMg2 [B2 O4 (OH) 2 ].2 Itisdifficulttosynthesizethiscompoundinthelaboratory .Recently ,weobtainedasimilarcompound 2MgO·B2 O3·1 5H2 Owhenwetriedtopreparewhiskerof 2MgO·B2 O3·H2 Obythephasetransformationof 2MgO·2B2 O3·MgCl2 ·14H2 OinH3BO3solutionunderhydrothermalcondition .Itishope fultopreparewh…  相似文献   

6.
刘志宏  高世扬  胡满成  夏树屏 《中国化学》2002,20(12):1519-1522
IntroductionTherearemanykindsofmagnesiumborates ,bothnaturalandsynthetic .Aboratedoublesalt (2MgO·2B2 O3 ·MgCl2 · 14H2 O)namedchloropinnoitewasob tainedfromthenaturalconcentratedsaltlakebrine .1Inordertofindtheformingrelationbetweenthedoublesaltandmagnesium bora…  相似文献   

7.
The ZrO(NO3)2-H3PO4-CsF-H2O system was studied at 20°C along the section at a molar ratio of PO43−/Zr = 0.5 (which is of the greatest interest in the context of phase formation) at ZrO2 concentrations in the initial solutions of 2–14 wt % and molar ratios of CsF: Zr = 1−6. The following compounds were isolated for the first time: crystalline fluorophosphates CsZrF2PO4 · H2O, amorphous oxofluorophosphate Cs2Zr3O2F4(PO4)2 · 3H2O, and amorphous oxofluorophosphate nitrate CsZr3O1.25F4(PO4)2(NO3)0.5 · 4.5H2O. The compound Cs3Zr3O1.5F6(PO4)2 · 3H2O was also isolated, which forms in a crystalline or glassy form, depending on conditions. The formation of the following new compounds was established: Cs2Zr3O1.5F5(PO4)2 · 2H2O, Cs2Zr3F2(PO4)4 · 4.5H2O, and Zr3O4(PO4)1.33 · 6H2O, which crystallize only in a mixture with known phases. All the compounds were studied by X-ray powder diffraction, crystal-optical, thermal, and IR spectroscopic analyses.  相似文献   

8.
CaSnO3 was synthesized by the polymeric precursor method, using different precursor salts as (CH3COO)2Ca·H2O, Ca(NO3)2·4H2O, CaCl2·2H2O and CaCO3, leading to different results. Powder precursor was characterized using thermal analysis. Depending on the precursor different thermal behaviors were obtained. Results also indicate the formation of carbonates, confirmed by IR spectra. After calcination and characterization by XRD, the formation of perovskite as single phase was only identified when calcium acetate was used as precursor. For other precursors, tin oxide was observed as secondary phase.  相似文献   

9.
The isopiestic method has been used to determine the osmotic coefficients of the binary solutions Cs2SeO4(aq) at T =  298.15 K from (1.090 to 4.591)mol · kg  1. The molalities m of (m1Cs2SeO4 + m2NiSeO4)(aq) have been investigated by physicochemical analysis. The crystallization of a new double salt Cs2SeO4· NiSeO4· 6H2O has been established. The Pitzer ion-interaction model has been used for thermodynamic analysis of the results obtained. The thermodynamic data needed (binary and ternary parameters of ionic interaction, thermodynamic solubility products) have been calculated and the theoretical solubility isotherm has been plotted. The experimentally obtained and the calculated solubilities are in very good agreement. The standard molar Gibbs energy of the synthesis reaction ΔrGmoof the double salt Cs2SeO4· NiSeO4· 6H2O from the corresponding simple salts Cs2SeO4and NiSeO4· 6H2O, as well as the standard molar Gibbs energy of formation ΔrGmohave been determined.  相似文献   

10.
The equilibrium solubility of the quaternary system RbCl-PrCl3-HCl-H2O was determined at 298.15 K and the corresponding equilibrium diagram was constructed in this paper. The quaternary system is complicated with three equilibrium solid phases, RbCl, RbPrCl4 · 4H2O (1:1 type) and PrCl3 · 6H2O, of which the new compound RbPrCl4 · 4H2O was found to be congruently soluble in the system. The new compound obtained was identified and characterized by the methods of X-ray diffraction, thermogravimetry, and differential thermogravimetry. The compound loses its crystal water by one step at 343 K to 453 K. The standard molar enthalpy of solution of RbPrCl4 · 4H2O in deionized water was measured to be −24.53 ± 0.22 kJ mol−1 by heat conduction microcalorimetry. Its standard molar enthalpy of formation was calculated to be −2743.20 ± 1.09 kJ mol−1.  相似文献   

11.
The enthalpies of solution of NaRb[B4O5(OH)4]·4H2O in approximately 1 mol dm−3 aqueous hydrochloric acid and of RbCl in aqueous (hydrochloric acid + boric acid + sodium chloride) were determined. From these results and the enthalpy of solution of H3BO3 in approximately 1 mol dm−3 HCl(aq) and of sodium chloride in aqueous (hydrochloric acid + boric acid), the standard molar enthalpy of formation of −(5128.02 ± 1.94) kJ mol−1 for NaRb[B4O5(OH)4]·4H2O was obtained from the standard molar enthalpies of formation of NaCl(s), RbCl(s), H3BO3(s) and H2O(l). The standard molar entropy of formation of NaRb[B4O5(OH)4]·4H2O was calculated from the Gibbs free energy of formation of NaRb[B4O5(OH)4]·4H2O computed from a group contribution method.  相似文献   

12.
The two complexes, [RE(Gly)4(Im)(H2O)](ClO4)3(s)(RE = Eu, Sm), have been synthesized and characterized. The standard molar enthalpies of reaction for the following reactions, RECl3·6H2O(s)+4Gly(s)+Im(s)+3NaClO4(s) = =[RE(Gly)4(Im)(H2O)](ClO4)3(s)+3NaCl(s)+5H2O(l), were determined by solution-reaction colorimetry. The standard molar enthalpies of formation of the two complexes at T = 298.15 K were derived as Δf H mΘ {Eu(Gly)4(Im)(H2O)}(ClO4)3(s)} = = −(3396.6±2.3) kJ mol−1 and Δf H mΘ {Sm(Gly)4(Im)(H2O)}(ClO4)3(s)} = −(3472.7±2.3) kJ mol−1, respectively.  相似文献   

13.
The calcium fluoride solid electrolyte Galvanic cell: (-) Pt, U3O8(s) + UO2F2(s) + BaUF6(s) + BaF2(s) | CaF2(s) | NiO(s) + NiF2(s), Pt (+) was used to measure the standard molar Gibbs energy of formation of BaUF6(s). From the measured emf values of the cell and required Gibbs energy values from the literature, Δf G m° (T) of BaUF6(s) has been calculated. The pseudo-binary phase diagram of BaF2–UF4 system was calculated by minimization of Gibbs energies of the phases present in the system. The stability domain of BaUF6(s) has been calculated from the chemical potential diagram of Ba–U–F–O system at 800 K.  相似文献   

14.
The CaBr2? MnBr2? H2O and CdBr2? MnBr2? H2O systems at 25°C have been studied. Two new double salts, CaBr2 · MnBr2 · 8 H2O and 4 CdBr2 · MnBr2 · 10 H2O, have been found. It was shown that for all known systems of the type MX2? M′X2? H2O (M, M′ ? Mg, Ca, Mn, Fe, Co, Ni, Cu, Zn, Cd; X ? Cl, Br), double salts are formed in all cases when both M2+ and M′2+ are p6, d5-HSS or d10 ions as well as in some cases when only one of the metal ions has these configurations. A comparison is made of the type and number of the double salts formed in a chloride and the corresponding bromide system.  相似文献   

15.
Summary.  Calcium sulfate occurs in nature in form of three different minerals distinguished by the degree of hydration: gypsum (CaSO4·2H2O), hemihydrate (CaSO4·0.5H2O) and anhydrite (CaSO4). On the one hand the conversion of these phases into each other takes place in nature and on the other hand it represents the basis of gypsum-based building materials. The present paper reviews available phase diagram and crystallization kinetics information on the formation of calcium sulfate phases, including CaSO4-based double salts and solid solutions. Uncertainties in the solubility diagram CaSO4–H2O due to slow crystallization kinetics particularly of anhydrite cause uncertainties in the stable branch of crystallization. Despite several attempts to fix the transition temperatures of gypsum–anhydrite and gypsum–hemihydrate by especially designed experiments or thermodynamic data analysis, they still vary within a range from 42–60°C and 80–110°C. Electrolyte solutions decrease the transition temperatures in dependence on water activity. Dry or wet dehydration of gypsum yields hemihydrates (α-, β-) with different thermal and re-hydration behaviour, the reason of which is still unclear. However, crystal morphology has a strong influence. Gypsum forms solid solutions by incorporating the ions HPO4 2−, HAsO4 2−, SeO4 2−, CrO4 2−, as well as ion combinations Na+(H2PO4) and Ln3+(PO4)3−. The channel structure of calcium sulfate hemihydrate allows for more flexible ion substitutions. Its ion substituted phases and certain double salts of calcium sulfate seem to play an important role as intermediates in the conversion kinetics of gypsum into anhydrite or other anhydrous double salts in aqueous solutions. The same is true for the opposite process of anhydrite hydration to gypsum. Knowledge about stability ranges (temperature, composition) of double salts with alkaline and alkaline earth sulfates (esp. Na2SO4, K2SO4, MgSO4, SrSO4) under anhydrous and aqueous conditions is still very incomplete, despite some progress made for the systems Na2SO4–CaSO4 and K2SO4–CaSO4–H2O. Corresponding author. E-mail: daniela.freyer@chemie.tu-freiberg.de Received December 17, 2002; accepted January 10, 2003 Published online April 3, 2003  相似文献   

16.
0IntroductionTherearemanykindsofhydratedcalciumbo-rates,bothnaturalandsynthetic.Someofthemarematerialsusedinglass,potteryandporcelainenamelindustry,especiallyinunalkaliglassindustry.4CaO·5B2O3·7H2O,calledpriceite,isacalciumboratemin-eral,notfoundinCaO-B…  相似文献   

17.
The solubility of MnSeO3-SeO2-H2O system was studied in the temperature region 25–300°C. The compounds of the three-component system were identified by the Schreinemaker’s method. The phase diagram of manganese(II) selenites was drawn and the crystallization fields for the different phases were determined. Depending on the conditions for hydrothermal synthesis, MnSeO3·H2O, MnSeO3·3/4H2O, MnSeO3·l/3H2O and MnSe2O5 were obtained. The different phases were proven and characterized by chemical, powder X-ray diffraction and thermal analyses, as well as IR spectroscopy. The kinetics of dehydration and decomposition of MnSeO3·H2O was studied under non-isothermal heating. Based on 4 calculation procedures and 27 kinetic equations, the values of activation energy and pre-exponential factor in Arrhenius equation were calculated for both processes.  相似文献   

18.
Thermodynamics of formation of carnallite type double salts   总被引:1,自引:0,他引:1  
The solubility of the systems RbCl–MgCl2–H2O, RbBr–MgBr2–H2O and CsBr–MgBr2–H2O have been investigated by the physicochemical analysis method at 25°C and formation of carnallite type double salts was established. The Pitzer model is used to calculate the thermodynamic functions needed to plot the solubility isotherms of the systems. The results obtained are in good agreement with the experimental data. The free energies of formation of carnallite and bromcarnallite type double salts from simple salts and the standard molar energies of formation are estimated.  相似文献   

19.
The changes in stabilization energy upon the formation of intermolecular hydrogen, dihydrogen and lithium bond complexes between C2B3H7, LiH and HF have been investigated using MP2 method with aug-cc-pVDZ basis set. The interaction of HF with nido-C2B3H7 could occur through the formation of B–H···H–F, C–H···F–H and B–C···H–F classical and non-classical hydrogen bonds. The B–C bonds in backbone of the C2B3H7 as electron donor interact with σ* orbital of HF as electron acceptor. Also interaction of LiH with nido-C2B3H7 resulted in B–C···Li–H and B–H···LiH lithium bonds as well as C–H···H–Li dihydrogen bond complexes. In some of these complexes, LiH interacts with B–C bonds. Results are indicating that more stable complexes belong to interaction of HF and LiH with backbone of the nido-C2B3H7. The AIM and NBO methods were used to analyze the intermolecular interactions; also the electron density at the bond critical point and the charge transfer of obtained complexes were studied.  相似文献   

20.
In the ternary system LiCl–CsCl–H2O the binary salt LiCl·2CsCl·4H2O was formed. Its structure was proved by the X-ray structural analysis. The binary compound formed in the aqueous solution by the structurally-forced insertion mechanism.  相似文献   

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