The ZrV2D6 crystal structure

Abstract We have studied by neutron powder diffraction the crystal structure of the maximum deuteride ZrV 2 D 6 based on the cubic Laves phase ZrV 2 . The structure is orthorhombic, space group Pnma (No. 62), cell parameters: a =5.5738(3) A, b =5.6996(3) A, c =7.9942(3) A. The arrangement of the metal atoms, Zr and V, is the same as in the initial ZrV 2 . Three D-atoms are ordered in the tetrahedral interstices Zr+3V, and other three D-atoms are ordered in the tetrahedral interstices 2Zr+2V. Distances between the nearest-neighbour D-atoms are ∼2.1 A. The ZrV 2 D 6 structure can be considered as a derivative of the Spinel-type structure found earlier in ZrTi 2 D 4 . Unlike the Spinel-type structure, where four D-atoms ought to be located in Zr+3V interstices, in ZrV 2 D 6 one of these atoms is replaced by three atoms located in the nearest 2Zr+2V interstices. The replacement differs for adjacent cells and is directed by the propagation vector k =(001).