Selected thermodynamic data for reactions involving auxiliary compounds and complexes

The procedure for the selection of data for selenium has been the following  

A complete set of thermodynamic data for the polymorphs of solid selenium, the liquid, and the gas molecules Se (g), = 1 to 8, was derived in the review by Mills [74MIL]. This work has been a valuable source of information, but several important later studies have appeared. A compilation of data for the equilibrium between liquid selenium and saturated selenium vapour was made by Rao [82RAO]. The work was mainly based on the contribution by Rau [74RAU] and the selection of data sources was limited. 

Selenium melts at (494.2 + 0.2) K [80WUN/SHU] and the thermodynamic properties of Se(l) are required for this work in the evaluation of high temperature measurements of selenium vapour pressures. The value accepted for the enthalpy of fusion is that of Gronvold [73GR02], who performed very accurate measurements of the thermodynamic properties of selenium in the temperature range 298 to 1000 K  

The liquid selenium is easily supercooled and undergoes a glass transition at 303.4 K. The heat capacity expression derived by [8IGAU/SHU] for the liquid is based on the work in [73GR02] and [80SHU/GAU] in the temperature ranges 500 to 1000 K and 330 to 520 K, respectively. The expression is selected here, 

No experimental values are available for the heat capacity of liquid selenium above 1000 K. For this work a constant value equal to the value at 1000 K was used in evaluations of data above 1000 K  

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Table IV-2 Selected thermodynamic data for reactions involving auxiliary compounds and complexes used in the evaluation of thermodynamic data for the NEA-TDB Project data. All ionic species listed in this table are aqueous species. Unless noted otherwise, all data refer to 298.15 K and a pressure of 0.1 MPa and, for aqueous species, a standard state of infinite dilution (/ = 0). The uncertainties listed below each value represent total uncertainties and correspond in principle to the statistically defined 95% confidence interval. Systematically, all the values are presented with three digits after the decimal point, regardless of the significance of these digits. The reference listed for each entry in this table indicates the NEA-TDB Review where the corresponding data have been...

Table lV-2 Selected thermodynamic data for reactions involving auxiliary compounds and complexes.74... 

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