Article ID Journal Published Year Pages File Type
9530361 Geochimica et Cosmochimica Acta 2005 17 Pages PDF
Abstract
The third step in our analysis involved consideration of ternary solid solutions with CaCO3 as the major end-member and any two of the seven considered Eu trace end-members. It was found that the three datasets can only be reproduced simultaneously with the ternary ideal solid solution EuH(CO3)2 - EuO(OH) - CaCO3, setting GEuH(CO3)2⁎ = −1773 kJ mol−1 and GEuO(OH)⁎ = −955 kJ mol−1, whereas all other end-member combinations failed. Our results are consistent with time-resolved laser fluorescence data for Cm(III) and Eu(III) indicating that two distinct species are incorporated in calcite: one partially hydrated, the other completely dehydrated. In conclusion, our study shows that substitution of trivalent for divalent cations in carbonate crystal structures is a more complex process than the classical isomorphic divalent-divalent substitution and may need consideration of multicomponent solid solution models.
Related Topics
Physical Sciences and Engineering Earth and Planetary Sciences Geochemistry and Petrology
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