Xia Shuping

FT-IR and Raman spectroscopic study of hydrated borates

Abstract FT-IR and Raman spectra of 27 hydrated borates are recorded and reexamined. On the basis of the spectra by Janda and Heller with boron isotope substitution and by Zha at different temperatures, the probable assignment of vibration spectra of monoborates, diborates, triborates, tetraborates, pentaborates, and hexaborates are given. The bands of symmetric pulse vibration of the corresponding polyborate anions are also indicated.

Prediction of the component solubility in the ternary systems HClLiClH2O, HClMgCl2H2O and LiClMgCl2H2O at 0 °C and 20 °C using the ion-interaction model

Abstract Component solubility in HClLiClH2O, HClMgCl2H2O and LiClMgCl2H2O systems of high ionic strength at 0°C and 20°C are calculated by using the Pitzers ion-interaction model and parameters derived from a least-squares optimization procedure which couples activity coefficient with solubility data. Excellent agreement with experimental solubility for ternary mixtures indicates that the model can be successfully used to predict the component solubility of salt lake brine systems that contain high concentration of LiCl. For all of the systems containing a high concentration of HCl, measurements of the activities of the complex compounds are not available, hence the evaluation of the values for the mixing parameters θMN and ΨMNX relied on solubility data in subsystems. The prediction also indicates that the parameters used do not vary linearly with the temperature, thus the algorithm used in order to calculate the parameters of LiCl at different temperatures is presented here. Based on the predictions of the solubility, the solubility curves of six ternary systems are constructed.

FT-IR and Raman spectroscopic analysis of hydrated cesium borates and their saturated aqueous solution

Hydrated cesium borates have been synthesized by the reaction of Cs(2)CO(3) with H(3)BO(3) aqueous solution. After reaction equilibria were reached, liquid and solid phases were separated and the FT-IR difference and Raman spectra of each phase were recorded, respectively. The assignments of the recorded FT-IR absorption frequencies and Raman shift are given. The main polyborate anions and their interaction in borate aqueous solution have been proposed. The relations between the existing forms of polyborate anions and the crystallizing solid phases, Cs(2)B(4)O(7).5H(2)O and CsB(5)O(8).4H(2)O, have been gained.

Thermochemistry of tetrahydrated rubidium pentaborate

Abstract The enthalpies of solution of RbB 5 O 8 ·4H 2 O in approximately 1 mol · dm −3 aqueous hydrochloric acid and of RbCl in aqueous (hydrochloric acid+boric acid) were determined. From these results and the enthalpy of solution of H 3 BO 3 in approximately 1 mol · dm −3 HCl(aq), the standard molar enthalpy of formation of −(4837.27±4.03) kJ · mol −1 for RbB 5 O 8 ·4H 2 O was obtained from the standard molar enthalpies of formation of RbCl(s), H 3 BO 3 (s), and H 2 O(l). The standard molar entropy of formation of RbB 5 O 8 ·4H 2 O was calculated from the thermodynamic relation with the standard molar Gibbs free energy of formation of RbB 5 O 8 ·4H 2 O computed from a group contribution method.

Chemistry of borate in salt lake brine. XIV. phase transition and kinetics of dehydration during heating of MgO · 3B2O3 · nH2O

Abstract The temperature and enthalpy of dehydration or recrystallization of synthetic MgO · 3B 2 O 3 · n H 2 O ( n = 5, 6,7,7 1 2 ) during heating having been determined by DTA, TG, DTG and DSC. The products have been verified by X-ray powder diffraction, infrared spectrograms and chemical analysis and the thermochemical reactions have been given. The phase composition of the recrystallization at high temperature were confirmed as crystal-state 2MgO · 3B 2 O 3 and amorphous B 2 O 3 by physical analysis after the phase separated by esterification between B 2 O 3 and methol alcohol. Using TG and DTG data, the kinetic parameters have been calculated by computer and the kinetic equations of non-isothermo-dehydration reactions have been given.