Crystal structure of silver carbonate iodide Ag(10)(CO(3))(3)I(4)

The title silver carbonate iodide, Ag(10)(CO(3))(3)I(4), deca­silver(I) tris­(carbonate) tetra­iodide, was recently reported as a precursor of the new superionic conductor Ag(17)(CO(3))(3)I(11). Ag(10)(CO(3))(3)I(4), was prepared by heating a stoichiometric powder mixture of AgI and Ag(2)CO(3) at 430 K. A single-crystal suitable for X-ray diffraction analysis was obtained by slow cooling of a melt with an AgI-rich composition down from 453 K. Ag(10)(CO(3))(3)I(4) exhibits a layered crystal structure packed along [10[Image: see text]], in which Ag atoms are inter­calated between the layers of hexa­gonally close-packed I atoms, and CO(3) groups. Up to now, Cs(3)Pb(2)(CO(3))(3)I is the only other compound containing carbonate groups and iodide ions registered in the Inorganic Crystal Structure Database.