Intracrystalline oxygen isotope effects in CuSO4·5H2O and their dependence on crystallization temperature

In copper sulfate pentahydrate the water molecules occupy three different sites, connected with different oxygen isotope ratios. Results of measurements of the change of these isotope ratios with crystallisation temperature are reported. The temperature dependence found here provides the basis for the determination of crystallisation temperatures of hydrated crystals from such intracrystalline oxygen isotope fractionation. Suppositions necessary for the application of this method are discussed.