Vapor pressure of indium chloride and some implications for the In-Se system

The optical absorbance of the vapor over InCl in the ultraviolet spectrum was measured. Comparison with the published vapor pressure yields a Beer's law constant of 0.00143 atm-cm for the 267.6 nm peak, and a 1273 K optical path. The spectrum is found to match unidentified peaks found in a recent study of the In-Se system. The amount of InCl in the In-Se samples of the recent study was calculated and was found to be by weight and of negligible influence on the partial pressures obtained there. However, on the basis of the results obtained here and on those from the recent study of the In-Se system, it appears likely that the published partial pressure of the subselenide over 33.3 at.%Se (In-Se) is in error and is actually that of an InCl impurity.