Phase Equilibrium System of CsCl鈥揟bCl3鈥揌Cl(7.6 mass %)鈥揌2O at 298.2 卤 0.1 K and Fluorescent and Thermal Properties of Its Solid-Phase Compounds in the System

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• 作者：Hui Wang ; Qi-Chao Yang ; Li Li
• 刊名：Journal of Chemical & Engineering Data
• 出版年：2013
• 出版时间：April 11, 2013
• 年：2013
• 卷：58
• 期：4
• 页码：1034-1038
• 全文大小：289K
• 年卷期：v.58,no.4(April 11, 2013)
• ISSN：1520-5134

文摘

The solubility data of the quaternary system CsCl鈥揟bCl₃鈥揌Cl(7.6 mass %)鈥揌₂O at 298.2 K were determined, and the corresponding phase diagram according to central projection data on the trigonal basal face CsCl鈥揟bCl₃鈥揌₂O was plotted. The diagram includes three invariant points and four crystallization fields corresponding to CsCl, Cs₅TbCl₈路6H₂O, Cs₂TbCl₅路6H₂O, and TbCl₃路6H₂O. Two new solid-phase compounds of Cs₅TbCl₈路6H₂O and Cs₂TbCl₅路6H₂O, which are congruently soluble in the system, were isolated and characterized by the methods of powder X-ray diffraction, thermogravimetric, and differential thermal analysis. The standard molar enthalpies of solution for the two compounds of Cs₅TbCl₈路6H₂O and Cs₂TbCl₅路6H₂O were measured to be (60.64 卤 0.28) and (14.08 卤 0.45) kJ路mol^鈥? by heat conduction microcalorimetry under the conditions of infinite dilution, and their standard molar enthalpies of formation were calculated to be 鈭?5087.1 卤 1.7) kJ路mol^鈥? and 鈭?3764.2 卤 1.0) kJ路mol^鈥?. The fluorescence excitation and emission spectra of Cs₅TbCl₈路6H₂O and Cs₂TbCl₅路6H₂O were measured. The results show that upconversion spectra exhibit for Cs₅TbCl₈路6H₂O at 500 nm and 545 nm and for Cs₂TbCl₅路6H₂O at 495 nm and 545 nm excited at 750 nm, and the upconversion intensity increases with the increase of TbCl₃ contents in CsCl.