Isosymmetrical phase transition in alpha-YbV4O8.

The structure of YbV4O8 is related to the CaFe2O4 structure type. VO6 octahedra form a three-dimensional framework with tunnels in which the Yb3+ ions are incorporated. Two different polymorphs alpha and beta are known and differ mainly in the arrangement of the Yb ions within the framework.