New mixed valent vanadium monophosphate with an intersecting tunnel structure Ba2V5O8(PO4)4

Abstract

A new mixed valent vanadium monophosphate Ba₂V₅O₈(PO₄)₄ has been synthesized. It crystallizes in the space group I1m1 with a=7.6405(1), b=22.777(1), c=11.6157(7) Å and β=103.38(1)°. Its framework consists of [V₄P₄O₂₂ ]_∞ layers of corner sharing polyhedra, interconnected by VO₄ tetrahedra which delimit tunnels in which the barium atoms are located. The vanadium atoms exhibit three kinds of coordination; pyramidal, octahedral and tetrahedral, in the same framework.