High-pressure x-ray absorption spectroscopy study of tin tungstates

Room-temperature pressure-dependent (0-25 GPa) x-ray absorption spectroscopy at the W L_1,3 -edges of α-SnWO₄ and β-SnWO₄ was performed using a dispersive setup and a high-pressure nanodiamond anvil cell. The detailed analysis of experimental x-ray absorption near-edge structure and extended x-ray absorption fine structure data suggests that upon increasing pressure, a displacement of tungsten atoms by about 0.2 Å toward the center of the WO₆ octahedra occurs in α-SnWO₄, whereas the coordination of tungsten atoms changes from tetrahedral to distorted octahedral in β-SnWO₄.