AgI[(MoO)(IO)]: a new polar material synthesized from the structural modulation of molybdenyl iodate architectures by polarizable cation (Ag) and anion (I).

A new polar material AgI[(MoO)(IO)], which contains the extended 2D [(MoO)(IO)] molybdenyl iodate framework found in the known noncentrosymmetric material K[(MoO)(IO)], has been synthesized through the conventional hydrothermal method at 200 °C. It crystallizes in the orthorhombic system space group Pna2 with a = 8.0072(2) Å, b = 21.2678(6) Å, c = 7.3241(2) Å, and V = 1247.26(6) Å. Its structure features 2D corrugated [(MoO)(IO)] anionic layers with neighboring anionic layers stitched through 1D [IAg] cationic chains to form a 3D structure. The 1D [IAg] cationic chain acts as the template for parallel alignments of the polar iodate anions along the c axis in 2D [(MoO)(IO)] anionic layers, which leads to the polar structure of the material. Second-harmonic generation (SHG) measurements on AgI[(MoO)(IO)] show a moderate SHG efficiency of about 0.7 times that of the KDP reference under 1064 nm laser radiation. In addition, the thermogravimetric analyses (TGA) and optical measurements of the compound were also carried out.