Sublimation pressures of a-CdSe obtained in experimental studies

In the aqueous phase, Umland and Wallmeier [80UML/WAL] studied the reduction of selenite at the mercury electrode in the presence of Cd by polarography, see Appendix A. The solubility product of CdSe(s) was obtained from the position of the half-wave potential of the second reduction step, HgSe(s) + Cd + 2e CdSe(s) + 

to be log,p AT°(, (CdSe, s, 298.15 K) = - (31.2 2.0). Combined with CODATA for Cd and the selected value for Se, it corresponds to AfG°(CdSe, s, 298.15 K) = - (127.2 + 11.8) kJ-mol. The value is not in harmony with the value obtained by extrapolation of high temperature data. Since the validity of the polarographic method has not been documented, the value of AfG°(CdSe, oc, 298.15 K) obtained from the extrapolation of the high temperature data has been selected. 

After the assessment of the thermodynamic properties of a-CdSe was made by the review, the heat capacity measurements made by Pashinkin, Maikova, and Mikhailova [2002PAS/MAL] have appeared. The measurements were performed in the temperature range 500 to 760 K and the result does not differ significantly from the values calculated from the selected heat capacity expression. The results therefore do not affect any of the selected thermodynamic properties of a-CdSe. 

Chukhlantsev [56CHU] prepared cadmium selenite by mixing a 0.1 M sodium selenite solution with the equivalent amount of a cadmium chloride solution. The product was amorphous. Chemical analysis confirmed the 1 1 ratio between Cd and Se(lV). The solubility of the specimen in dilute solution of nitric or sulphuric acid was measured at 293 K. The data have been recalculated as described in Appendix A, [56CHU]. The result for 

Toropova [57TOR] measured the shift of the polarographic half-wave potential of Cd in 0.15 to 0.50 M sodium selenite solutions. The solutions also contained 

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Figure V-19 Sublimation pressures of a-CdSe obtained in experimental studies.

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