Vapor Pressure of Ice Containing D 2 O

Abstract

The vapor pressures of solid D₂O and ice containing D2O in various amounts were measured with an oil manometer. The result gives the lowest vapor pressure for D₂O ice ever obtained. The observed value for ice with different proportions of D2O and H₂O agreed well with the values calculated on the assumption that the vapor pressure of HDO is the geometrical mean of those of H₂O and D₂O and that the equilibrium constant of isotopic exchange is 4. The fractionation factor of D between ice and vapor phases increases from 1.128 at 0°C to 1.210 at —38°C.