CRYSTAL-STRUCTURE INVESTIGATIONS OF TL2AG I3 AND NAAGI2-CENTER-DOT-3H(2)O

Tl2AgI3 was synthesized by the reaction of TlI with AgI in aqueous HI (25%) in a pressure vessel. The compound crystallizes in the rhombohed ral space group R (3) over bar; a = 1044,3(2); c = 1993,5(3)pm; Z = 9. The crystal structure contains trinuclear anions [Ag3I8](5-) and [ITl 6](5+) octahedra. The anions are composed of two AgI4-tetrahedra which are connected to an AgI6 octahedron via common faces. Single crystals of NaAgI2 . 3H(2)O were formed by reaction of NaI with AgI in aqueous solution. The compound crystallizes in the orthorhombic space group P bca with lattice parameters a = 711,2(2); b = 939,8(3); c = 2462,2(4) pm; Z = 8. The crystal structure is built up by polymeric layers (2)(i nfinity)[AgI3/3I1/21/2-] of corner sharing AgI4 tetrahedra (GaOCl type ) and (1)(infinity)[Na(H2O)(4/2)(H2O)I-1/2(1/2+)] octahedra chains.