Structural, optical and mechanical properties of Di Imidazolium Oxalate Monohydrate single crystals

A novel organic crystal, Di Imidazolium Oxalate Monohydrate (DIOM) has been grown by slow evaporation method using water solvent. The synthesized crystal's packing, molecular geometry, and crystalline structure were studied by single crystal X-ray diffraction analysis. The grown crystal crystallises in the Pnna space group of the Orthorhombic crystal system. Using powder XRD analysis, the (h k l) planes were identified. The molecular structure is further confirmed by FTIR, 1H and 13C NMR analysis. Hardness measurement was carried out with the increment in the loads from 10 to 50 g to understand the hardness nature of the grown crystal and the results suggested that the material belongs to the soft category. The hardness parameters such as yield strength, stiffness constant for the different loads were calculated, and the results indicate that the hardness parameters increase with the load. The crystal possesses a direct and an indirect band gap of 4.18 and 3.75 eV respectively with a lower cut-off wavelength of 269 nm. The UV-vis-NIR spectrum shows a low absorption in the visible region. The crystal possesses a refractive index of 1.4397. The crystal was found to be stable up to 90 degrees C and the melting point was found to be 191 degrees C using the capillary tube method.