Synthesis, Optical, Dielectric, SHG, Magnetic and Visible Light Driven Catalytic Studies on Compounds Belonging to the Swedenborgite Structure

Abstract

A new compound, InBaZn3GaO7, with swedenborgite structure along with transition metal (TM) substituted variants has been prepared. The structure contains layers of tetrahedral ions (Zn2+/Ga3+) connected by octahedrally coordinated In3+ ion forming the three‐dimensional structure with voids where the Ba2+ ions occupy. The TM substituted compounds form with new colors. The origin of the color was understood based on the ligand‐field transitions and metal to metal charge transfer (MMCT) transitions . The near IR reflectivity studies indicate that the Ni – substituted compounds exhibit good near – IR reflectivity behavior, making them possible candidates for ‘cool‐pigments’. The temperature dependent dielectric studies indicate that the InBaZn3GaO7 compound undergoes a phase transition at ~ 360 °C. The compounds are active towards second harmonic generation (SHG). Magnetic studies show the compounds, InBaZn2CoFeO7 and InBaZn2CuFeO7 to be anti‐ferromagnetic in nature. The copper containing compounds were found to be good catalysts, under visible light, for the oxidation of aromatic alkenes. The many properties observed in the swedenborgite structure‐based compounds suggests that the mineral structure offers a fertile ground to investigate newer compositions and properties.