High-energy X-ray diffraction study of Ni-doped sodium metaphosphate glasses

The structures of four Ni-doped sodium metaphosphate glasses (NiO)x(NaPO3)1−x [x = 0.009, 0.018, 0.033 and 0.074] were investigated by high-energy synchrotron X-ray diffraction (E = 120.0 keV). With increasing NiO content the development of the first nickel–oxygen correlation could clearly be observed in the corresponding pair correlation functions. The high-resolution X-ray diffraction data enabled the separation of the first Ni–O, Na–O and O–O correlations for a-(NiO)0.074(NaPO3)0.926. The first average Ni–O distance is 2.02(2) Å and the coordination of Ni with O, which was also determined by EXAFS at the Ni K-absorption edge, is 6. Interatomic distances between phosphorus and bridging (P–OB) or non-bridging oxygen (P–OT) could be discriminated in the structures of all investigated samples.