Some peculiarities of interactions in the Hf2Fe−H2 system at low temperatures and high pressures

Hydride formation was studied in the Hf2Fe−H2 system at hydrogen pressure of up to 2000 atm in a temperature range from 195 to 295 K. Hydride phases of different compositions were studied by the X-ray diffraction method. The hydrogenation reaction in the system can take two pathways to form two stable hydride phases depending on the conditions of initial hydrogenation. Absorption of hydrogens at a pressure of about 2000 atm yields a hydride which contains two H atoms per metal atom. Models of the arrangement of hydrogen atoms in the crystal lattice of hydride phases were suggested.