  The magnetic properties of a novel cobalt-based hydrogen vanadate,
Co13.5(OH)6(H0.5VO3.5)2(VO4)6, are reported. This new magnetic material was
synthesized in single-crystal form using a conventional hydrothermal method.
Its crystal structure was determined from single-crystal X-ray diffraction data
and was also characterized by scanning electron microscopy. Its crystal
framework has a dumortierite-like structure consisting of large hexagonal and
trigonal channels; the large hexagonal channels contain one-dimensional chains
of face-sharing CoO6 octahedra linked to the framework by rings of VO4
tetrahedra, while the trigonal channels are occupied by chains of disordered
V2O4 pyramidal groups. The magnetic properties of this material were
investigated by DC magnetic measurements, which indicate the occurrence of
antiferromagnetic interactions.
