THE THERMODYNAMIC PROPERTIES OF RADIUM
THE THERMODYNAMIC PROPERTIES OF RADIUM
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DOI：
10.1016/0016-7037(85)90264-9
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发表时间：
1985-01-01
影响因子：
5
通讯作者：
RIESE, AC
中科院分区：
文献类型：
--
作者：
LANGMUIR, D;RIESE, AC
根据经验数据计算了Ra溶液和Ra固体的焓、吉布斯自由能和熵，必要时也进行了估计。C和1巴。估算是基于对Ca、Sr和Ba络合物和固体的热力学性质的外推断，根据阳离子半径和电荷半径函数绘制，并使用离子对形成的Fuoss或静电数学模型（Langmur, 1979）。结果是log K和。delta。H0 (association) （kcal/mol）值为；为RaOH+ 0.5和1.1；RaCl+ -0.10和0.50；* *图形* *。2.5和1.07；和* *图形* *。2.75和1.3 Log Ksp和。delta。h。degree。RaCO3(c)和RaSO4(c)的解离（kcal/mol）值分别为-8.3和-2.8,-10.26和-9.4。根据已公布的分布系数(D)，对铅盐和较轻碱土中微量Ra固溶体进行了评价，其中D .simeq。（mM2+）(NRaX)/(mRa2+)(NMX)(m和N分别为盐X中Ra和阳离子m的水摩尔浓度和摩尔分数。利用经验固溶体数据，推导了硫酸盐和碳酸盐矿物中高达100℃的微量Ra的固溶体焓和吉布斯自由能。C.结果表明，在每种情况下，D值都随着温度的升高而降低。在硫酸盐和碳酸盐矿物中，D值减小的顺序依次为：硬石膏>天青石>角长石>重晶石>文石>锶长石>铜长石>铜长石。
The enthalpy, Gibbs free energy, and entropies of aqueous Ra species and Ra solids were evaluated from empirical data, or estimated when necessary for 25.degree. C and 1 bar. Estimates were based on extrapolation of the thermodynamic properties of Ca, Sr, and Ba complexes and solids plotted against cationic radii and charge to radius functions, and the use of the Fuoss or electrostatic mathematical models of ion pair formation (Langmur, 1979). Resultant log K and .DELTA.H0 (association) (kcal/mol) values are; for RaOH+ 0.5 and 1.1; RaCl+ -0.10 and 0.50; .**GRAPHIC**. 2.5 and 1.07; and .**GRAPHIC**. 2.75 and 1.3 Log Ksp and .DELTA.H.degree. (dissociation) (kcal/mol) values for RaCO3(c) and RaSO4(c) are -8.3 and -2.8, and -10.26 and -9.4, respectively. Trace Ra solid solution in salts of Pb and of the lighter alkaline earths, was appraised based on published distribution coefficient (D) data, where D .simeq. (mM2+)(NRaX)/(mRa2+)(NMX)(m and N are the aqueous molality and mole fraction of Ra and cation M in salt X, respectively. The empirical solid solution data were used to derive both enthalpies and Gibbs free energies of solid solution of trace Ra in sulfate and carbonate minerals up to 100.degree. C. Results show that in every case D values decrease with increasing temperature. Among the sulfate and carbonate minerals, D values decrease for the following minerals in the order; anhydrite > celestite > anglesite > barite > aragonite > strontianite > witherite > cerussite.