Synthesis, characterization and optical absorption studies of Na[Fe(CN)4(C3H4N2)NO]2H2O crystals

Crystals of $$\rm{Na}\left[\rm{Fe}{\left(\rm{CN}\right)}₄\left({\rm{C}}₃{\rm{H}}₄{\rm{N}}₂\right)\rm{NO}\right]2{\rm{H}}₂\rm{O}$$ (SNP-d) have been prepared by photochemical route using sodium nitroprusside (SNP) as precursor complex. The crystals were subjected to various characterization techniques such as energy dispersive X-ray analysis, Fourier transform infrared, UV–visible spectroscopy and X-ray diffraction. From X-ray diffraction, it has been observed that SNP-d belongs to orthorhombic crystal system with primitive lattice. Crystallite size has been found to be 79.2 nm. Molecular structure of SNP-d depicts its non-centrosymmetric nature. As observed from UV–visible spectroscopy, SNP-d crystals form a double bandgap material, between which transitions have been found to be direct allowed. High value of refractive index and low value of reflectance, as obtained from Reddy, Anjaneyulu and Fresnel’s equations, indicate transparency of material to visible radiation. This is clearly justified from UV–visible spectra as the wavelength cutoff is around 300 nm.