Date Published: September 01, 2012
Publisher: International Union of Crystallography
Author(s): Mineo Sato, Tadashi Ishigaki, Kazuyoshi Uematsu, Kenji Toda, Hirokazu Okawa.
Crystals of dilithium manganese(II) silicate were grown under high-temperature hydrothermal conditions in the system LiOH—MnO2—SiO2. The title compound crystallizes in the βII-Li3PO4 structure type. The coordination polyhedra of all cations are slightly distorted tetrahedra (m symmetry for MnO4 and SiO4), which are linked by corner-sharing to each other. The vertices of the tetrahedra point to the same direction perpendicular to the distorted hexagonal close-packed (hcp) array of O atoms within which half of the tetrahedral voids are occupied by cations. In comparison with the previous refinement from powder X-ray data [Dominko et al. (2006 ▶). Electrochem. Commun.8, 217–222], the present reinvestigation from single-crystal X-ray data allows a more precise determination of the distribution of the Li+ and Mn2+ cations, giving a perfectly site-ordered structure model for both Li+ and Mn2+.
For background to structural studies of Li2MSiO4 (M = Mn, Fe, Co) compounds, see: Islam et al. (2011 ▶); Santamaría-Pérez et al. (2012 ▶); Setoguchi (1988 ▶); Yamaguchi et al. (1979 ▶). Polymorphism of Li2MnSiO4 was reported by Arroyo-de Dompablo et al. (2006 ▶, 2008 ▶); Belharouak et al. (2009 ▶); Dominko et al. (2006 ▶); Kokalj et al. (2007 ▶); Politaev et al. (2007 ▶); Wu et al. (2009 ▶); Zhong et al. (2010 ▶). For notation of Li3PO4 polymorphs, see: West & Glasser (1972 ▶). For theoretical studies of the redox potentials and Li migration paths of Li2MnSiO4, see: Kuganathan & Islam (2009 ▶); Mali et al. (2010 ▶); Duncan et al. (2011 ▶), and for NMR studies of this material, see: Sirisopanaporn et al. (2011 ▶). For the bond-valence method, see: Brown & Altermatt (1985 ▶). For crystallographic background, see: Cooper et al. (2002 ▶).