Crystal-Structures of (Nh₄)₂(AgI₃)_{∞/ ∞}.H₂O And (Nme₄)(Ag₂I₃)_∞/∞

Abstract

Single-crystal X-ray structure determinations of the title compounds at 295 K are reported. For (1), (NH₄)₂(AgI₃)∞/∞.H₂O, the structure is isomorphous with that reported previously for K₂AgI₃, being orthorhombic, Pbnm , a 21.20(2), b 10.84(1), c 4.629(3)Ǻ, Z 4, R 0.032 for 1211 'observed' independent reflections. Locations and refinement of an artefact modelled as a water molecule raises the possibility that other members of the isomorphous series may be monohydrates rather than anhydrous. (NMe₄)(Ag₂I₃)∞/∞, (2), is orthorhombic, Pnam , a 17.760(7), b 10.077(4), c 7.431(2)Ǻ, Z 4, R 0.043 for 977 'observed' independent reflections; the structure is a redetermination of better precision confirming the essential features of an earlier study and treating the cation in terms of an ordered rather than a disordered model.