An orthorhombic polymorph of the ultraphosphate YP5O14

Single crystals of yttrium pentaphosphate(V), YP5O14, were obtained by solid-state reaction. The orthorhombic title compound belongs to the family of ultraphosphates and is the second polymorph of this composition. It is isotypic with its Ho and Er analogues. The structure contains two bridging Q2-type PO4 tetrahedra and one branching Q3-type PO4 tetrahedron, leading to infinite ultraphosphate ribbons running along the a axis. The coordination polyhedron around the Y3+ cation may be described as distorted bicapped trigonal-prismatic. The YO8 polyhedra are isolated from each other. They are linked by corner-sharing to the O atoms of six Q2-type and of two Q3-type PO4 tetrahedra into a three-dimensional framework.