A new class of inorganic compounds containing dinitrogen-metal bonds

TGA of particular oxynitrides shows an unexpected intermediate phase between starting oxynitride and final oxide. Transition between this intermediate phase and the oxide step, studied by high resolution mass spectrometry, reveals that this phenomenon can be ascribed to a nitrogen retention. We deduce the general formulation Mn+ On/2Nx. Particular properties of those phases are. low density, structure type analogous to the one of their oxynitride precursor and a nitrogen binding energy, measured by XPS, near 403 eV. By comparison to the binding energy range of organometallic dinitrogen complexes, we assume the presence of M-N=N-M entities included in an oxide lattice with cationic defect structure. (C) 1997 Elsevier Science Limited.