Rubidium vanadium(III) vanadyl(IV) phosphate, RbV(VO)(PO)(HPO): crystal chemistry and low-dimensional magnetism.

In this paper, we present the synthesis and characterization of a rubidium vanadium(III) vanadyl(IV) phosphate, obtained under hydrothermal conditions. The new compound crystallizes in the triclinic space group 1̄ with the unit cell parameters = 9.637(1), = 12.254(2), = 12.336(2) Å, = 105.82(1), = 104.81(1) and = 102.75(1)°. Its crystal structure was determined by single crystal X-ray diffraction. The structure of RbV(VO)(PO)(HPO) is formed from V-centered octahedra sharing all oxygen vertices and one edge with phosphate tetrahedra to form ribbons parallel to the [011] direction. These ribbons are further linked VO polyhedra in a three-periodic framework with channels running parallel to the and axes. Rb atoms occupy positions inside the framework channels. The title compound achieves a long range ordered antiferromagnetic state at = 2.1 K and formally demonstrates a high value of the magnetic frustration parameter equal to the ratio of the Weiss and Néel temperatures ||/ = 15, which can be attributed to the reduced dimensionality of the magnetic subsystem. At < , the magnetization curve exhibits the signature of the 1/3 plateau.