The work is devoted to X-ray diffraction research of defected niobium oxide nonuniform (NON) arrays and niobium oxide nanocolumns formed by electrochemical anodizing. The results obtained allow to make an assumption about the probable presence of significant amount of NbO, NbO0.7, Nb2O5 and small amount of NbO2, and Al in the composition of defected NON and the presence of all these substances in the nanocolumns of niobium oxide except NbO0.7, but in smaller quantities. A comparative analysis of the NON structure and the nanocolumns makes it possible to isolate, probably, significant amount of Nb0.94O0.06, Nb6O in the defective nanocolumns, which was not found in NON.