Ultraviolet Light Effects on Cobalt–Thiourea Complexes Crystallization

Abstract

In this work, a cobalt–thiourea complexes crystal synthesis was carried out comparatively with and without ultraviolet light assistance (λ = 253 nm), and its effect was studied. Through the solvent evaporation technique, crystalline forms were obtained, which were analyzed and characterized by different techniques: Raman spectroscopy, X-ray diffraction (XRD), and digital optical microscopy. Crystal’s shape changes were observed when comparing those obtained from the solution with and without ultraviolet (UV) assistance. It was found that the UV light effect on the crystals causes a structural modification of the complex synthesized in the (022) (120) planes and without UV assistance in the (002), (111), (131¯), and (132¯) planes. It is also possible to observe an increase in intensity by Raman spectra identified as Co–S bonds (297 cm−1) for crystals synthesized with UV assistance.

Keywords

• crystal growth process
• UV light assistance
• cobalt–thiourea complex
• thiourea compounds
• crystal morphology