Nickel titanate, a distorted ilmenite-type oxide, is a promising inorganic yellow pigment with potential applications in ceramic coloration and optoelectronic materials. In this work, the structural, electronic, optical, and colorimetric properties of NiTiO \(_3\) were investigated through a combined experimental and first-principles approach. NiTiO \(_3\) powders were synthesized by a solid-state reaction using NiO and TiO \(_2\) precursors. X-ray diffraction (XRD) confirmed the formation of the rhombohedral ilmenite phase, and UV–Vis spectroscopy revealed strong absorption in the visible region associated with the characteristic yellow coloration. First-principles calculations were performed using the Quantum ESPRESSO package within the DFT+U framework to investigate the structural, electronic, and magnetic properties, while the optical absorption spectrum was calculated using the Yambo code with a long-range correction (LRC) approach. The results predicted an electronic band gap of about 2.62 eV, in good agreement with experimental observations. The calculated optical spectra and the derived CIELAB color coordinates closely matched the experimentally observed yellow color, demonstrating the capability of first-principles calculations to predict the colorimetric properties of inorganic pigments.
