Organic and Inorganic Chemistry

Materials crystallizing in noncentrosymmetric (NCS) structures may show certain properties such as pyroelectricity, piezoelectricity, ferroelectricity and nonlinear properties. To achieve a macroscopic NCS structure, bismuth, tellurium and NO3- were used in the synthesis as constituents. Since the lone pairs on bismuth and tellurium are stereochemically active, they can exhibit asymmetric environment. The π-conjugated electron in the NO3 group can also facilitate the nonlinear optical property. The hydrothermally synthesized material reveals a layered nonpolar structure with a weak hydrogen bond interaction. The compound crystallizes in the orthorhombic space group, P-21-21-21. Two types of existing telluriums, Te4+ and Te6+ show see-saw and octahedral coordination environment with oxide ligands, respectively. Bi3+ cations are linked to oxygen atoms and form BiO9 and BiO10 polyhedra. NO3- is connected to the bismuth atoms. Powder second-harmonic generation(SHG) measurements indicate that the NCS material has a SHG efficiency of 20 times that of α-SiO2