OXYGEN LINKAGES IN NEODYMIUM HEPTAMOLYBDATE SINGLE-CRYSTALS - AN XPS STUDY

Single crystals of neodymium heptamolybdate (Nd2Mo7O24. 27H(2)O) are g rown in sodium metasilicate gel by the diffusion of neodymium nitrate (upper reactant) into the set gel impregnated with a mixture of molybd enum trioxide, ammonium hydroxide and concentrated nitric acid (lower reactant). Oscillation X-ray diffraction pattern shows that neodymium heptamolybdate is single-crystalline in nature, while infrared absorpt ion spectrum establishes the presence of molybdate group and water of crystallization. X-ray photoelectron spectroscopic studies of neodymiu m heptamolybdate single crystals establish the presence of neodymium a nd molybdenum in their oxide states and the oxygens in the sample are shown to exist as (i) terminal oxygen (Mo=O), (ii) bridging oxygen (Mo -O-Nd) and (iii) oxygen of lattice water (H-O-H).