Crystal structure of silver carbonate iodide Ag10(CO3)3I4.

The title silver carbonate iodide, Ag10(CO3)3I4, deca-silver(I) tris-(carbonate) tetra-iodide, was recently reported as a precursor of the new superionic conductor Ag17(CO3)3I11. Ag10(CO3)3I4, was prepared by heating a stoichiometric powder mixture of AgI and Ag2CO3 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. Ag10(CO3)3I4 exhibits a layered crystal structure packed along [10], in which Ag atoms are inter-calated between the layers of hexa-gonally close-packed I atoms, and CO3 groups. Up to now, Cs3Pb2(CO3)3I is the only other compound containing carbonate groups and iodide ions registered in the Inorganic Crystal Structure Database.