Solid–liquid equilibria in the systems cesium bromide + holmium bromide + water and cesium bromide + holmium bromide + hydrobromic acid (~11.7 mass %) + water at T = 298.15 K. (October 2021)

• Record Type: Journal Article
• Authors: Qiao, Zhan-Ping; Yang, Qi-Chao; Qin, Ling
• Is Part Of: Journal of chemical thermodynamics. Volume 161(2021)
• Publication Date: 2021-10
• Subjects: Phase equilibrium -- Cesium bromide -- Holmium bromide -- Standard molar enthalpy of formation; Thermodynamics -- Periodicals; Thermochemistry -- Periodicals; Thermodynamique -- Périodiques; Thermochimie -- Périodiques; Thermochemistry; Thermodynamics; Periodicals; 541.369
• DOI: 10.1016/j.jct.2021.106562
• Languages: English
• ISSNs: 0021-9614

Abstract

Highlights: Solubility was measured for CsBr + HoBr3 + H2 O and CsBr + HoBr3 + HBr (~11.7%) + H2 O systems at T = 298.15 K. The corresponding phase diagrams were plotted. Cs3 Ho2 Br9 ·16H2 O was characterized. Δf H θ m of Cs3 Ho2 Br9 ·16H2 O was determined. Abstract: The (Solid–Liquid) phase equilibria for the systems of cesium bromide + holmium bromide + water and cesium bromide + holmium bromide + hydrobromic acid (~11.7 mass %) + water at T = 298.15 K were researched by the isothermal dissolution equilibrium method. According to the experimental data, the phase diagrams of the two systems were depicted. There were two invariant points, three invariant curves, and three crystallization fields (CsBr, Cs3 Ho2 Br9 ·16H2 O, HoBr3 ·8H2 O) in the two phase diagrams. Cs3 Ho2 Br9 ·16H2 O was incongruently soluble in the two systems. The solubility of HoBr3 measured in water at T = 298.15 K is 65.41 mass %. The compound Cs3 Ho2 Br9 ·16H2 O was investigated using chemical analysis, XRD and TG-DTG analysis. The standard molar enthalpy of solution of Cs3 Ho2 Br9 ·16H2 O in water was measured to be −(5.54 ± 0.28) kJ/mol by a microcalorimetry, and its standard molar enthalpy of formation was determined as being –(7846.5 ± 1.2) kJ/mol.