  We report on the pressure evolution of the electronic and crystal structures
of the noncentrosymmetric antiferromagnet EuCoGe3. Using a diamond anvil cell,
we performed high pressure fluorescence detected near-edge x-ray absorption
spectroscopy at the Eu L3, Co K, and Ge K edges and synchrotron powder x-ray
diffraction. In the Eu L3 spectrum, both divalent and trivalent Eu peaks are
observed from the lowest pressure measurement (~2 GPa). By increasing pressure,
the relative intensity of the trivalent Eu peak increases, and an average Eu
valence continuously increases from 2.2 at 2 GPa to 2.31 at~50 GPa. On the
other hand, no discernible changes are observed in the Co K and Ge K spectra as
a function of pressure. With the increase in pressure, lattice parameters
continuously decrease without changing I4mm symmetry. Our study revealed a
robust divalent Eu state and an unchanged crystal symmetry of EuCoGe3 against
pressure.
