Atomic Weight of Fluorine

Abstract

WE have recently pointed out¹ that there appears to be no evidence for the view expressed by Prof. Moles that methyl fluoride made by Collie's method consists of a constant boiling mixture with methane. It was, however, suggested by Prof. Moles that both Collie's critical data and also the compressibility at 0° C. (1.011) which we deduced from microbalance measurements are incorrect owing to the above cause. We have accordingly carried out a series of determinations of the critical constants of methyl fluoride prepared both by Collie's method and also by the methyl sulphate-potassium fluoride method used by Prof. Moles. We have also measured the compressibility coefficient of methyl fluoride made by the latter method.