17O magic angle spinning (MAS) NMR has been used to determine the nature of oxygen exchange in ZrW(2)O(8). A highly effective isotopic labelling technique has been developed and 1D NMR and 2D exchange spectroscopy (EXSY) experiments have revealed that mutual exchange occurs between all oxygen sites, even at temperatures considerably below the alpha to beta order-disorder phase transition.

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The use of solid-state (17)O NMR to determine local chemical environment and to characterise oxygen dynamics is illustrated in studies of zirconium tungstate, ZrW(2)O(8), and tungsten oxide, WO(3). Simple 1D magic-angle spinning (MAS) NMR allows the chemical environments in ZrW(2)O(8) to be readily characterised, and the use of a combination of one- and two-dimensional experiments to characterise oxygen dynamics in its cubic phase is reviewed. Combining local information about structure and dynamics from NMR with long-range structural information from diffraction allows a comprehensive picture of the material to be developed. Recent work is described that uses first principles calculation of NMR parameters to probe subtle asymmetries in the WO(6) octahedra that form the structural motif in WO(3). NMR is shown to be a highly sensitive probe of local structure, allowing different models derived from high-quality neutron diffraction studies to be distinguished. The density functional theory (DFT) calculations allow clear correlations between (17)O chemical shifts and distortions of the structure to be established.

The dynamics of oxygen motion in ZrW(2)O(8) have been characterized using (17)O solid-state NMR. Rates of dynamic exchange have been extracted from magnetization transfer experiments over a temperature range of 40 to 226 degrees C, and distinct values for the associated activation barrier have been observed on either side of the order/disorder phase transition at approximately 175 degrees C. A detailed model for the dynamical process is proposed, which reconciles the observation of continuing oxygen dynamics in the low-temperature phase with the static order implied by earlier X-ray diffraction studies.

There has been considerable debate in the literature about the true room-temperature structure of ZrP2O7 and related materials. In this article we describe how a combination of information from solid-state 31P NMR and powder diffraction data can be used to determine the structure of this 136 unique-atom material. The structure has been solved using a combination of simulated annealing and Rietveld refinement performed simultaneously on X-ray and neutron diffraction data. Despite the close to cubic metric symmetry of the material, we show how its true orthorhombic structure (space group Pbca) can be refined to a high degree of precision.