High purity In2O3 crystals were synthesized by the chemical vapour transport (CVT) as confirmed by X-ray Photoelectron Spectroscopy (XPS) using survey, core-levels and valence band scans of the samples. Further, high energy resolution XPS spectra revealed perfectly bonded In 3d configuration and excluded the presence of metallic In0, concurrently, the dual band observed for O 1s configuration was interpreted in term of the additional defectiveness in the oxygen sublattice. The valence band as measured by XPS is in agreement with the calculated one using DFT approach, and an insignificant shift of valence band toward Fermi level (about 0.05 eV) caused by the presence of the defects was established. Moreover, the energetics of the primarily defects were calculated and the trends were set in the perspective of XPS measurements. Altogether we make CVT In2O3 crystals ready to be used for the onward studies and technical applications.