A peroxoniobium phosphate derived from NbOPO4. 3H2O

Abstract The reaction between white NbOPO 4 ·3H 2 O and H 2 O 2 produces yellow NbO(O 2 ) 0.5 PO 4 ·2H 2 O. This reaction can be considered as an intercalation process since the Nb|P ratio and the basic layered structure are preserved. The X-ray powder diffraction pattern of the new phosphate can be indexed on a tetragonal unit cell with a =6.488(1) A and c =16.030(4) A. X-ray powder thermodiffractometry, DTA–TGA, Raman and IR spectroscopies, and magnetization measurements are used to characterize the new compound. The intercalated dioxygen bonds directly to niobium, replacing the water. Half of the initial NbO 6 groups change to NbO 7 since dioxygen acts a chelated ligand interacting with Nb through the two oxygens simultaneously.