Single crystal growth by gel technique and characterization of lithium hydrogen tartrate

Single crystal growth of lithium hydrogen tartrate by gel encapsulation technique is reported. Dependence of crystal count on gel density, gel pH, reactant concentration and temperature are studied and the optimum conditions for these crystals are worked out. The stoichiometric composition of the grown crystals is determined using EDAX/AES and CH analysis. The grown crystals are characterized by X-ray diffraction, FUR and Uv-Visible spectroscopy. It is established that crystal talk under orthorhombic system and space group P-222 with the cell parameters as: a=10.971 angstrom, b=13.125 angstrom and c=5.101 angstrom; alpha=90.5 degrees, beta=gamma=90 degrees. The morphology of the crystals as revealed by SEM is illustrated. Crystallite size, micro strain, dislocation density and distortion parameters are calculated from the powder XRD results of the crystal. UV-vis spectroscopy shows indirect allowed transition with an optical band gap of similar to 4.83 eV. The crystals are also shown to have high transmittance in the entire visible region. Dependence of dielectric constant, dielectric loss and conductivity on frequency of the applied ac field is analyzed. The frequency-dependent real part of the complex ac conductivity is found to follow the universal dielectric response: sigma ac (omega) similar to omega s. The trend in the variation of frequency exponent with frequency corroborates the fact that correlated barrier hopping is the dominant charge-transport mechanism in the present system. (C) 2014 Elsevier B.V. All rights reserved.