Physicochemical Analysis of Tetrakis (Thiourea) Palladium Chloride: A Prospective Non Linear Optical Crystal

Abstract

The solubility test and nucleation kinetics studies of Tetrakis (thiourea) palladium chloride (TTPC) have been carried out and optical quality crystals of TTPC have been harvested by means of slow evaporation method. The single crystal X-ray diffraction studies revealed the orthorhombic structure and Pna21 space group of the crystals. To ascertain the stoichiometry and the purity of the crystals, elemental analysis has been performed. The etching studies of the crystal suggested the dimensional nucleation mechanism. Fourier Transform Infrared spectral studies have been employed in order to establish the metal—sulphur coordination prevailing in the crystal. The Ultra Violet transmittance study has been conducted to calculate the transmittance, band gap energy, Urbach’s energy, nature of electronic transitions, reflectance, refractive index, optical and electrical conductivities, extinction coefficient and electrical susceptibility. The mechanical stability of the TTPC crystals has been examined by Vicker’s hardness test in terms of hardness number, elastic stiffness constant, Meyer’s Index, minimum level of indentation load, load dependent constant, brittleness index and corrected hardness. Kurtz method has been adopted which showed the phase matching nature of TTPC and concluded that TTPC showed 1.15 times second harmonic generation efficiency as that of KDP. By using the dielectric and ac conductivity study, the activation energy values of the electrical process have been measured. Using theoretical approach, important solid state parameters such as valence electron plasma energy, Penn gap, Fermi energy and polarisability have been derived. The photoconductivity studies revealed the negative conductivity of the title crystal.