Hydrogen Isotope Fractionation in the Water of Hydration of Crystals

Author: Bild, Richard Wayne

Year: 1968

Degree: Bachelor's thesis

Advisor: Epstein, Samuel

Committee Member: Unknown, Unknown

Option: Chemistry

DOI: 10.7907/fpyh-ft50

Abstract

Hydrogen isotope fractionation in the .water of hydration of several crystals was studied~ Dehydration of CuSO4·5H2O in stages shows that in general water containing deuterium is preferentially retained in the crystal. Some Variations from this general trend are observed at the composition of CuSO4·3H2O and CuSO4·H2O. These variations can be explained as being due to a change in the manner in which the water coming off was held in the crystal. Similar behavior is observed for ZnSO4·7H2O. Rehydration of anhydrous CuSO4 with distilled water indicates that heavy water is preferentially incorporated into the hydrated crystals. Experiments circulating water vapor over CuSO4·5H2O crystals indicate that isotopic equilibrium is obtained only very slowly. The time at room temperature is probably well over 68 hours for vapor that started with about 30% less heavy water than the expected equilibrium value. Water samples were analyzed by passing the vapor over hot uranium metal to reduce the hydrogen in the water to hydrogen gas and using a mass spectrometer to obtain the D/H ratios relative to a standard sample.

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