Preparation and characterization of vanadyl phosphates modified with two trivalent metal cations

Abstract The layered crystalline solids with the general formula M x 1 M z 2 (H 2 O) x+z (VO) 1−x−z PO 4 ·nH 2 O (M 1 , M 2 = trivalent Al, Cr, Fe, Mn; x, z = 0.04–0.15, n = 2–3) were prepared by refluxing V 2 O 5 with aqueous solutions of phosphoric acid and M 1 and M 2 metal salts. Compounds were characterized by X-ray diffraction (XRD) and thermogrametric and differential thermal analysis (TG-DTA) techniques. The elementary cell of these compounds is tetragonal, with space symmetry group either P 4/ nmm or P 4/ n. The dependence of basal spacings on different relative humidities of atmosphere was followed. The hydration water of the as-prepared compounds depends on the nature and amount of the trivalent metals M 1 and M 2 .