Structure and dehydration of the pyrochlore system NaW2−yMoyO6+δ·nH2−zO between 10 and 675 K

The temperature dependence of the structure of the pyrochlore NaW2−yMoyO6+δ·nH2−zO has been investigated using a variety of diffraction and spectroscopic methods. The positions of OH−/H2O molecules in the structure have been determined. Increases in temperature induce small lattice parameter changes, which are thought to result from movement of the H2O molecules in the pyrochlore lattice.