CsBr-TmBr_3-H_2O和CsBr-TmBr_3-HBr(～13%)-H_2O(298.15K)的相平衡及新固相化合物的热力学和荧光性质

Equilibria for the CsBr-TmBr_3-H_2O and CsBr-TmBr_3-HBr(～13%)-H_2O Systems at 298.15 K and Thermodynamic and Fluorescent Properties of New Solid-phase Compound

采用等温溶度法测量了三元体系Cs Br-Tm Br3-H2O和四元体系Cs Br-Tm Br3-HBr（~13%）-H2O在298.15 K时的相平衡溶度数据,并绘制了相应的相图.三元体系和四元体系均由3个平衡固相Cs Br,Cs3Tm2Br9·16H2O和Tm Br3·8H2O构成.新固相化合物Cs3Tm2Br9·16H2O在三元和四元体系均是固液异成分溶解的化合物,且其结晶区随平衡液相中氢溴酸浓度的增加而增大.用X射线粉末衍射仪（XRD）、热重分析仪和荧光光谱仪对Cs3Tm2Br9·16H2O进行了表征.结果表明,当用712 nm光激发时,Cs3Tm2Br9·16H2O在471 nm处具有上转换发光性能.用微量热仪测定了Cs3Tm2Br9·16H2O在无限稀释下的标准摩尔溶解焓为-（11.63±0.46）k J/mol,确定其标准摩尔生成焓为-（7826.2±1.2）k J/mol.

The phase equilibria of the ternary system Cs Br-Tm Br3-H2 O and the quaternary system Cs BrTm Br3-HBr（ ~ 13%）-H2 O at 298. 15 K were investigated by the isothermal solubility method. Based on the experimental data,the corresponding phase diagrams were plotted. In the ternary system,three crystallization regions corresponding to Cs Br,Cs3Tm2Br9·16H2O and Tm Br3·8H2O were found. Similarly,there were three crystallization regions corresponding to Cs Br,Cs3Tm2Br9·16H2O and Tm Br3·8H2O in the quaternary system. The phase diagrams of the ternary and quaternary systems were compared and a new double salt Cs3Tm2Br9·16H2O is formed which is incongruently soluble in the two systems; the area of the crystallization region of Cs3Tm2Br9·16H2O increases with the increasing concentration of HBr in the equilibrium liquid phase. The new solid-phase compound Cs3Tm2Br9·16H2O was characterized by chemical analysis,X-ray diffraction（ XRD） and thermal gravity-differential thermal gravity（ TG-DTG） techniques. The fluorescence excitation and emission spectra of Cs3Tm2Br9·16H2O were measured. Upconversion emission of the new solid phase was found at 471 nm when excited at 712 nm. The standard molar enthalpy of solution of Cs3Tm2Br9·16H2O in water was measured to be-（ 11. 63 ± 0. 46） k J / mol by microcalorimetry under the condition of infinite dilution and its standard molar enthalpy of formation was determined as-（ 7826. 2 ± 1. 2） k J / mol.