Acentric La(IO)(OH) and La(IO)(NO): Partial Substitution of Iodate Anions in La(IO) by Hydroxide or Nitrate Anion.

Partial substitution of iodate anions in La(IO) by OH or NO anion led to acentric La(IO)(OH) and chiral La(IO)(NO). The structure of La(IO)(OH) can be seen as a complex three-dimensional (3D) network composed of two-dimensional [La(IO)(OH)] cationic layers that are further bridged by remaining iodate anions, or alternatively as a 3D network composed of one-dimensional [La(IO)(OH)] cationic columns being further interconnected by additional iodate anions, while the structure of La(IO)(NO) can be seen as a novel 3D structure with planar NO groups serving as linkage between the [La(IO)] triple layers. Compared to La(IO), both compounds show considerably wide band gaps and enhanced thermal stability. La(IO)(NO) shows a moderate second harmonic generation (SHG) response of ∼0.6 times that of KDP (KHPO), a wide band gap of 4.23 eV, and a high LDT value (22 × AgGaS). Optical property measurements, thermal analysis, as well as theoretical calculations on SHG origin, were performed. It can be deduced that partial substitution of iodate anions can be a facile route to design new noncentrosymmetric metal iodates with novel structure and potential application.