The Rb analogue of grimselite, Rb6Na2[(UO2)(CO3)3]2(H2O).

The crystal structure of the Rb analogue of grimselite, rubidium sodium uranyl tricarbonate hydrate, Rb6Na2[(UO2)(CO3)3]2(H2O), consists of a uranyl hexagonal bipyramid that shares three non-adjacent equatorial edges with carbonate triangles, resulting in a uranyl tricarbonate cluster of composition [(UO2)(CO3)3)]. These uranyl tricarbonate clusters form layers perpendicular to [001] and are interconnected by NaO8 polyhedra. The title compound is isostructural with grimselite, with a reduced occupancy of the H2O site (25% versus 50% in grimselite).