COMPRESSIBILITY OF DIHYDRIDES OF TRANSITION-METALS

The crystal structures and equations of state of the transition metal dihydrides VD1.9, NbD1.9, TiD2, ScD2 and YD2 have been studied by neutron diffraction in the pressure range up to 6-13 GPa. It has been established that the structure of the deuterides (CaF2 type) is stable within the whole pressure range. An increase in tetragonal splitting under pressure was observed in TiD2. The compressibilities of vanadium and niobium deuterides are close to those of the pure metals but the compressibilities of titanium, scandium and yttrium deuterides are less than those of the metals. These results can be explained in terms of the electronic structures of the dihydrides.