Molar Heat Capacity and Heat of Fusion of Silicon Tetraiodide

抄録

The molar heat capacity of silicon tetraiodide, SiI₄, used as a source material in the iodide process of silicon preparation was measured by means of an adiabatic calorimeter which can be used for continuous measurement.
The molar heat capacities of solid and liquid silicon tetraiodide obtained were C_p=19.59+0.0209 T cal/mol deg and C_p=35.25+0.00987 T cal/mol deg, respectively. The melting point was 120.5°C, and the heat of fusion and the entropy of fusion were 4.70 kcal/mol and 11.9 cal/mol deg, respectively. The heat contents, free energy functions and standard entropy of S₂₉₈^°=43.7 cal/mol deg were derived for silicon tetraiodide from the experimental values and thermochemical data. Moreover, the molar heat capacities of pure chromium, fused quartz and highly pure silicon were also measured, the values of which were in good agreement with those in the previous literature.