Synthesis and characterization of strontium tartrate tetrahydrate crystal using silica gel method

Abstract

In the present study, strontium tartrate tetrahydrate crystals were grown using the silica gel method. Optimum growth parameters were obtained by varying molar concentration, volume of upper reactant solution, and pH of gel mixture at ambient temperature (31 °C). Large size crystal (9 × 8 × 4 mm3) of strontium tartrate tetrahydrate were obtained when the pH of the gel mixture was 4.2 and upper reactant had a molar concentration of 1.5 M and volume of 20 ml. As grown crystal was characterized using different techniques viz. Powder X-ray Diffraction (PXRD), Fourier Transform Infrared spectroscopy (FTIR), Energy Dispersive Analysis of X-ray (EDAX), and UV–vis spectral analysis. Analysis of Powder X-ray diffraction data carried out in the 2θ range 10°–60° revealed that as grown crystal had an orthorhombic structure with space group P2 2 2 and unit cell parameters a = 9.8865 Å, b = 10.0448 Å, c = 9.5186 Å, α = β = γ = 90°. Various vibrational peaks of hydroxyl group (OH) at wavenumber 3170.42, 3384.44, 3536.72 cm−1, carbonyl (CO) group at 1601.88 cm−1 were observed in FTIR spectroscopy. One peculiar peak at 478.2 cm−1 where one O− and was replaced by Sr2+ was also obtained in FTIR spectroscopy suggesting formation of strontium tartrate crystal. Energy dispersive analysis of X-ray confirms the presence of expected major elements like strontium, carbon, and oxygen in the crystal. UV–vis transmission spectrum of strontium tartrate tetrahydrate crystals was recorded in the wavelength range of 190 to 1100 nm. The energy bandgap estimated from transmission data is 5.64 eV. Non-linear Optical (NLO) competence of STT crystal is observed at 532 nm. The electrical property of pelletized samples was studied by dielectric measurement in the frequency range of 20 Hz–2 MHz at room temperature. It is observed that dielectric loss is very low at higher frequency.