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. (C) 2002 American Institute of Physics.