A PEROXONIOBIUM PHOSPHATE DERIVED FROM NBOPO4-CENTER-DOT-3H(2)O

The reaction between white NbOPO4. 3H(2)O and H2O2 produces yellow NbO (O-2)(0.5)PO4. 2H(2)O. This reaction can be considered as an intercala tion process since the Nb/P ratio and the basic layered structure are preserved. The X-ray powder diffraction pattern of the new phosphate c an be indexed on a tetragonal unit cell with a = 6.488(1) Angstrom and c = 16.030(4) Angstrom, X-ray powder thermodiffractometry, DTA-TGA, R aman and IR spectroscopies, and magnetization measurements are used to characterize the new compound. The intercalated dioxygen bonds direct ly to niobium, replacing the mater. Half of the initial NbO6 groups ch ange to NbO7 since dioxygen acts a chelated ligand interacting with Nb through the two oxygens simultaneously, (C) 1998 Academic Press.