Journal of

GEOsciences

  (Formerly Journal of the Czech Geological Society)

Original paper

Sofia A. Kalashnikova, Vladislav V. Gurzhiy

Synthesis and Crystal Structure of the New Uranyl Carbonate (NH₄,Na)₄[UO₂(CO₃)₃], and its relation to Čejkaite

Journal of Geosciences, volume 70 (2025), issue 4, 253 - 262

DOI: http://doi.org/10.3190/jgeosci.0063.26

Single crystals of a new uranyl carbonate (NH₄,Na)₄[UO₂(CO₃)₃] (1) have been prepared by evaporation at room temperature from aqueoussolution. The structure was solved by direct methods [orthorhombic, Cmcm, a = 15.712(3), b = 9.039(2), c = 8.915(3) Å, V = 1266.2(6) ų and Z = 4] and refined to R₁ =0.0314 (wR₂ = 0.0704). The crystal structure of the novel compound is based on pseudo-layered complexbuilt by [(UO₂)(CO₃)₃]^4- uranyl tricarbonate clusters (UTC) linked together through Na⁺ and NH₄⁺ ions. Such layered complexes of UTC are typical for a number of uranyl compounds of both natural and synthetic origin, including čejkaite. However, the relative arrangement of layers in 1 is distinct due to the specific interlayer content and can be described as a novel polytype.