  High-pressure phase of boron oxide, orthorhombic \b{eta}-B2O3, has been
studied in situ by synchrotron X-ray diffraction to 22 GPa and Raman scattering
to 46 GPa at room temperature. The bulk modulus of \b{eta}-B2O3 has been found
to be 169(3) GPa that is in good agreement with our ab initio calculations.
Raman and IR spectra of \b{eta}-B2O3 have been measured at ambient pressure,
all experimentally observed bands have been attributed to the theoretically
calculated ones, and the mode assignment has been performed. Based on the data
on Raman shift as a function of pressure, combined with equation-of-state data,
the Gr\"uneisen parameters of all experimentally observed Raman bands have been
calculated. \b{eta}-B2O3 enriched by 10B isotope has been synthesized, and the
effect of boron isotopic substitution on Raman spectra has been studied.
