Investigation of ZrFe2 and ZrCo2 Under Very High Pressure of Gaseous Hydrogen and Deuterium

New hydrides and deuterides of Laves cubic phases ZrFe 2 and ZrCo 2 were synthesized by high hydrogen (deuterium) pressure technique. For both Laves phases the symmetry of lattice does not change but a large expansion of lattice parameter (by 8% for ZrFe 2 and by 4.5% for ZrCo 2 ) occurs during hydrides (deuterides) formation. In contrast to the relatively stable hydride (if stored in an inert atmosphere) formed in ZrFe 2 , the ZrCo 2 H 2 decomposes easily at 25°C. Large lattice expansion of ZrFe 2 during the deuteride formation changes only slightly its magnetic properties.