Pressure–volume relationship of Ta

Pressure-volume (P–V) data were measured for Ta up to 69 GPa at T=298 K using angle-dispersive synchrotron x-ray diffraction in combination with diamond anvil cell techniques. Nitrogen and sodium were used as quasihydrostatic pressure media. The obtained P–V relation is compared to experimental and recent theoretical results. Some advantages and limitations of using Ta as a pressure marker in high-resolution x-ray diffraction experiments with diamond anvil cells are discussed.