title: A novel crystal polymorph of volborthite, Cu3V2O7(OH)2·2H2O.
abstract: A new polymorph of volborthite [tricopper(II) divanadium(V) heptaoxide dihydroxide dihydrate], Cu(3)V(2)O(7)(OH)(2)·2H(2)O, has been discovered in a single crystal prepared by hydrothermal synthesis. X-ray analysis reveals that the monoclinic structure has the space group C2/c at room temperature, which is different from that of the previously reported C2/m structure. Both structures have Cu(3)O(6)(OH)(2) layers composed of edge-sharing CuO(4)(OH)(2) octahedra, with V(2)O(7) pillars and water molecules between the layers. The Cu atoms occupy two and three independent crystallographic sites in the C2/m and C2/c structures, respectively, likely giving rise to different magnetic interactions between Cu(II) spins in the kagome lattices embedded in the Cu(3)O(6)(OH)(2) layers.
authors: Institute for Solid State Physics, University of Tokyo, Kashiwanoha 5-1-5, Kashiwa 277-8581, Japan. ishikawa@issp.u-tokyo.ac.jp
authors: Hajime
authors: H
authors: Ishikawa
authors: Jun-ichi
authors: J
authors: Yamaura
authors: Yoshihiko
authors: Y
authors: Okamoto
authors: Hiroyuki
authors: H
authors: Yoshida
authors: Gøran J
authors: GJ
authors: Nilsen
authors: Zenji
authors: Z
authors: Hiroi