Synthesis, characterization and evaluation of optically active polar semi-organic glycine-cobalt chloride crystals

Semi organic crystals of glycine Cobalt Chloride (GCC) exhibiting diverse colors were grown using the slow solvent evaporation method. The molecular structure was validated by characterization using various techniques, including Fourier-transform Infrared spectroscopy (FTIR), Mass spectra (MS), Atomic absorption spectroscopy (AAS), and powder X-ray diffraction (pXRD). Depending on the molar concentration of CoCl2, the crystals exhibited a monoclinic structure with space group P21/c at low concentration and a tetragonal structure with space group P43212 at high concentration. UV-Vis. spectral analysis revealed a decrease in the lower cut-off wavelength and an increase in the band gap from 5.779 eV to 5.929 eV with the augmentation of CoCl2concentration. Thermal analysis (gravimetric and differential scanning calorimetery indicated that the crystals maintain stability up to 250°C. Furthermore, the dielectric properties exhibited temperature and frequency nonlinear dependence confirming ferroelectric, piezoelectric characteristics and polarity. The good crystals' showed nonlinear optical activity and transparency in the Vis. light confirmed the possible application in the second harmonic generation.