Vanadium(IV)–Oxide Nanotubes: Crystal Structure of the Low-Dimensional Quantum Magnet Na2V3O7

Fibers of Na2V3O7 have been obtained by solid state reaction. This compound crystallizes in the trigonal system, space group P31c, with a=10.886(1) Å, b=9.5380(1) Å, V=978.87(2), Z=6, and ρ=3.163 g cm−1. The structure is built up by VO5 square pyramids connected via edges and apices to form fascinating vanadium(IV)–oxide nanotubes. The cohesion of the network is ensured by the sodium atoms which are located around the nanotubes. The inner diameter of the nanotube is close to 5 Å, which can accommodate the presence of a sodium atom Na1 inside the nanotube. Such geometry with all the vanadium atoms in the valence state IV should give interesting ionic conductivity and magnetic properties.