Cationic coordination compound Cs{sub 2}Hg{sub 3}I{sub 8} for IR NLO material: Synthesis, crystal growth and characterizations
Single crystals Cs{sub 2}Hg{sub 3}I{sub 8} of dimensions 5 × 3 × 4 mm{sup 3} were grown by solution growth method at room temperature and structurally characterized by single crystal X – ray diffraction. Cs{sub 2}Hg{sub 3}I{sub 8} compound crystallizes in a noncentrosymmetric space group Cm with the crystal data of a = 7.4415 Å, b = 21.6629 Å, c = 7.6726 Å, α, β = 90°, γ = 108.05° and Z = 2. The grown crystals were characterized by powder X – ray diffraction analysis and the various diffraction planes are indexed. The presence of functional groups was identified qualitatively by Fourier transform infrared and FT – Raman spectral analyses. Ultraviolet – visible spectral analyses shows that the crystal has low UV cut off at 388 nm combined with very good transparency of 98 % in a wide range. The optical band gap was estimated to be 3 eV. Mechanical hardness of the grown crystal Cs{sub 2}Hg{sub 3}I{sub 8} was determined. The dielectric response of the crystal with varying frequencies was studied. Differential scanning calorimetry (DSC) analysis shows that the grown crystal has very good thermal stability up to 97.5°C.