Metallic phase of hydrogen at the pressure 500GPa
  The first-principle method of mathematical modeling was used to calculate the structural, electronic, phonon, and other characteristics of the normal metallic phase of hydrogen at a pressure of 500 GPa. It has been shown that metal hydrogen having a lattice symmetry I41 / AMD cell is a stable phase under a high pressure hydrostatic compression. The resulting structure is a locally stable one with respect to the phonon spectrum. 
Nikolay Degtyarenko and Evgeny Mazur
cond-mat.supr-con