The deuterium site occupation in ZrV2Dsub(x) as a function of the deuterium concentration

The distribution of the deuterium atoms in the deuterated Laves-phase ZrV2Dsub(x) was measured by neutron powder diffraction for deuterium concentrations x of 1.5, 2.8 and 4.9. At low deuterium concentrations only the tetrahedral interstices formed by two zirconium and two vanadium atoms are occupied whereas at medium deuterium concentrations the interstices formed by one zirconium and three vanadium atoms are also populated. At high deuterium concentrations the occupancy of the latter interstices exceeds that of the former. The interstices formed by four vanadium atoms always remain empty. The results are analysed in the light of a cellular model of hydride stability. Good agreement is found between the calculated and the observed deuterium site occupancies. (Auth.)