Novel superstructure in the high-concentrated hydrogen solid solutions ZrV2Dx>4

A novel hydrogen superstructure with k = 0 is found to form in the hydrogen solid solutions ZrV2Dx in the concentration range 4 < x < 4.5. According to the neutron-diffraction investigation performed, it has tetragonal symmetry (a = 5.517 Å, c = 7.921 Å for ZrV2D4.32 at T = 10 K) and belongs to the space group I41/a. Four hydrogen atoms are arranged just as in the known superstructure ZrV2Dx<4, in the 2Zr + 2V tetrahedral interstices. The surplus hydrogen atoms, exceeding x = 4, locate in the uncommon 4V tetrahedral interstices. Distances between all hydrogen atoms exceed 2 Å.