Abstract: | Contributions to the Investigation of Inorganic Non-stoichiometric Compounds. XIV. Oxidation Products of Orthorhombic Nb12O29, Electron Optical Investigation An electron optical investigation shows that the orthorhombic starting material Nb12O29(BII) is well ordered. The oxidation products Nb2O5(Ox1BII) and Nb2O5(Ox2BII) are different from each other in structures as well as in their reactions. Nb2O5(Ox1BII) is unstable in the electron beam and differs from BII by characteristic point-defects. The radiation load can lead to the reduction to BII or to a transition into a defect structure with R-type-tunnels. The not well ordered structure of Nb2O5(Ox2BII) is stable in the electron beam. Characteristic is the sequence of [2×5] and [3×4] blocks, the latter in two different orientations. The observed composition O/Nb = 2.500 can be described by the present structural modell assuming vacant niobium tetrahedral sites. The large structural differences between the oxidation products of the orthorhombic and the monoclinic Nb12O29 are remarkable. |