Article thumbnail

Redetermination of synthetic warwickite, Mg3TiO2(BO3)2

By Tetsuya Kawano and Hisanori Yamane

Abstract

Single crystals of warwickite, trimagnesium titanium(IV) dioxide bis­(borate), Mg3TiO2(BO3)2, were prepared by slow cooling of the melt. The title compound is isotypic with Co3TiO2(BO3)2. In contrast to the previous refinement of warwickite [Moore & Araki (1974 ▶). Am. Mineral. 59, 985–1004], that reported only isotropic atomic displacement parameters for all atoms, anisotropic displacement parameters of all atoms were refined during the current redetermination. All atoms are situated on special positions (site symmetry .m.). One of the two Mg sites is statistically disordered with Ti atoms (ratio 1:1), while the other is fully occupied by Mg atoms. The occupancy ratio of the Mg and Ti atoms is similar to that reported in the previous study. Metal atoms (M) at the Ti/Mg and Mg sites are coordinated by six O atoms in form of distorted octa­hedra. Four edge-sharing MO6 octa­hedra form M 4O18 units, which are connected by common corners into layers parallel to (010). Adjacent layers are linked along [010] into a framework structure by sharing common edges. The B atoms are located in the triangular prismatic tunnels of the framework

Topics: Inorganic Papers
Publisher: International Union of Crystallography
OAI identifier: oai:pubmedcentral.nih.gov:3051737
Provided by: PubMed Central

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.

Suggested articles

Citations

  1. (1991). Acta Cryst.
  2. Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) x y z Uiso*/Ueq Occ.
  3. (1995). inorganic compounds Acta Cryst.
  4. (1985). of the Mg, Ti and B atoms were calculated with the bond valence parameters of 1.693 Å for Mg2+, 1.815 Å for Ti4+ and 1.371 Å for B3+ (Brese & O'Keeffe,
  5. (1974). show the coordination environments of the
  6. (1995). Synthetic warwickite-type oxyborates with general composition MII 3MIVO2(BO3)2 are known for