Acta Crystallographica Section B

Structural Science

Volume 55, Part 6 (December 1999)

research papers

Acta Cryst. (1999). B55, 953-962 [ doi:10.1107/S0108768199005467 ]

Crystal structure of layered bis(ethylenediamine)nickel hexavanadate as a new representative of the V₆O₁₄ series

P. Y. Zavalij, F. Zhang and M. S. Whittingham

Abstract: A new [Ni(NH₂CH₂CH₂NH₂)₂](V₆O₁₄) compound has been synthesized hydrothermally and was found to crystallize in the monoclinic system. The single-crystal X-ray data leads to a disordered structure, which can be decomposed into two ordered models with different stacking of the V₆O₁₄ layers. The structure of the layer is the same in both models and represents a new member of the V₆O₁₄ series. All known structures from this series are constructed from the same chain of square pyramids (SP), which share alternatively adjacent or opposite edges of their bases. The differences lie in the orientation of the SP chains which are joined together by sharing corners with tetrahedra to form the layers. Combinatorial analysis of the V₆O₁₄ structures was conducted, yielding ten possible symmetry groups for the series of V₆O₁₄ layers. The known structures belong only to the three simplest cases with the highest symmetry.

Keywords: Bis(ethylenediamine)nickel hexavanadate; Layer structure.