Iodide-Iodates M3[IO3]12·Ag4I, M = Bi, Tb, with a Framework Structure and High Second-Harmonic Generation Optical Response

• Published in: Inorganic chemistry Vol. 56; no. 3; pp. 1186 - 1192
• Main Authors: Belokoneva, Elena L, Stefanovich, Sergey Yu, Dimitrova, Olga V, Karamysheva, Alina S, Volkov, Anatoly S
• Format: Journal Article
• Language: English
• Published: American Chemical Society 06.02.2017
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/acs.inorgchem.6b02191

Single crystals of two new iodide-iodates, Bi3[IO3]12·Ag4I and Tb3[IO3]12·Ag4I, are synthesized in hydrothermal systems. The anionic parts in both iodide-iodates are characterized as a complex charged framework of isolated IO3 umbrella-like groups and large Bi­(Tb)–O polyhedra similar to those previously found in La3[IO3]12­[IO3]­(Pb3O). Broad channels along the c-axis contain compensators: (Ag3I)2+ umbrella-like groups and additional Ag+ ions which form Ag4 4+ tetrahedral clusters augmented with I– halogen. New iodates possess significantly higher second-order nonlinear optical characteristics compared to the previously known lead-containing compounds REE3[IO3]12­[IO3]­(Pb3O), REE = La, Pr, Nd. The difference is related to the polar ordering of umbrella-like (Ag3I)2+ groups in the channels in the new iodide-iodate. Additionally, planar-coordinated Ag atoms add three Ag atoms in umbrellas forming [Ag4I]3+ polar clusters in the channels.