VIBRATIONAL STUDIES OF BIS(THIOUREA) CADMIUM CHLORIDE AND TRIS(THIOUREA) ZINC-SULFATE SEMIORGANIC NONLINEAR-OPTICAL CRYSTALS

Single crystals of Bis(thiourea) cadmium chloride (BTCC), and Tris(thi ourea) zinc sulphate (TZnS) have been grown from saturated aqueous sol ution by slow evaporation method at room temperature. The laser Raman and FT-IR spectra on these crystals are recorded in the frequency rang e 50-4000 cm(-1). The spectral data of BTCC and TZnS are interpreted o n the basis of thiourea crystal vibrational data. The vibrational freq uencies in the FT-IR and Raman spectra of BTCC and TZnS establish that ZnSO4 and CdCl2 metal complex are coordinated with thiourea by the me tal to sulfur bonds. The effect of the metal complexation on thiourea molecule and nature of bands due to different vibrational modes have b een discussed. The lattice vibrational frequencies changes have also b een observed and analyzed.