Abstract
Experimental values of mixing entropy in the Tl-Te liquid system have been quoted as evidence against the inhomogeneous model for liquid semiconductors. The reliability of available experimental values of mixing entropy in the relevant systems is reviewed, and the particular difficulty of calculating the integral mixing entropy from experimental measurements in liquid semiconducting systems is discussed. It is found that the only measurements which are not extremely unreliable are those for the Tl-Te system, and even here the data for the Te-rich region cannot be interpreted theoretically without a considerable quantity of additional data. Previous theoretical analyses of the data are also reviewed, and are shown to suffer from the defect that at least two possible major contributions to mixing entropy have been ignored. The uncertainty in estimating the size of these contributions means that it is not possible to calculate molecule size from values of mixing entropy. A further complication is that there is experimental evidence that stoichiometric liquid T12Te is ionic rather than molecular.