Vapor Pressure of Ice Containing D2O

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Science  25 Sep 1964:
Vol. 145, Issue 3639, pp. 1454-1455
DOI: 10.1126/science.145.3639.1454


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.