Synthesis, growth, and structural, optical, mechanical, electrical properties of a new inorganic nonlinear optical crystal: Sodium manganese tetrachloride (SMTC)

Abstract

A new inorganic nonlinear optical single crystal of sodium manganese tetrachloride (SMTC) has been successfully grown from aqueous solution using the slow evaporation technique at room temperature. The crystals obtained using the aforementioned method were characterized using different techniques. The crystalline nature of the as-grown crystal of SMTC was analyzed using powder X-ray diffraction. Single-crystal X-ray diffraction revealed that the crystal belongs to an orthorhombic system with non-centrosymmetric space group Pbam. The optical transmission study of the SMTC crystal revealed high transmittance in the entire UV–vis region, and the lower cut-off wavelength was determined to be 240nm. The mechanical strength of the as-grown crystal was estimated using the Vickers microhardness test. The second harmonic generation (SHG) efficiency of the crystal was measured using Kurtz's powder technique, which indicated that the crystal has a nonlinear optical (NLO) efficiency that is 1.32 times greater than that of KDP. The dielectric constant and dielectric loss of the compound were measured at different temperatures with varying frequencies. The photoconductivity study confirmed that the title compound possesses a negative photoconducting nature. The growth mechanism and surface features of the as-grown crystals were investigated using chemical etching analysis.