Abstract

The crystal structure of beta-uranophane with the lattice constants a = 13.966(2), b = 15.443(4), c = 6.632(1) Å, β = 91.38°(2) has been refined. It shows that the space group is P21/a and that the basic structural features determined previously are correct. However, bond-strength sums, calculated using the refined interatomic distances, reveal that the apical oxygens of all SiO4 tetrahedra must be (OH)- ions and that the H bonds play as important a role as Ca in linking sheets that have the formula [(UO2)2(SiO3OH)2]2-. Hence the structural formula should be Ca(UO2)2(SiO3OH)2⋅5H2O instead of Ca(UO2)(UOOH)(SiO4)(SiO3OH)⋅4H2O as suggested earlier. Studies of the same mineral with dta, dtg, and infrared spectroscopy support this conclusion.

This content is PDF only. Please click on the PDF icon to access.

First Page Preview

First page PDF preview
You do not currently have access to this article.