Condensation Coefficients of Mercury Halides

Abstract

USING the method of Alty1, we have measured the coefficients of condensation (f) of the compounds mercuric chloride, bromide and iodide. A hemispherical cap of these salts was deposited by sublimation on the end of a glass tube which could be heated internally by boiling turpentine. The temperature of the cap surface was measured by a fine thermocouple while the salt evaporated in a high vacuum. The quantity of salt evaporated per unit time and area (M1) was determined by weighing the deposit on a surrounding glass tube immersed in liquid air. By calculating the maximum rate of evaporation (M2) from the formula of the kinetic theory of gases, where P is saturated vapour pressure (mm. mercury), M is molecular weight, t is time of evaporation, T is absolute temperature, one finds f = M1/M2.