Structural properties of Pb3Mn7O15 determined from high-resolution   synchrotron powder diffraction
  We report on the crystallographic structure of the layered compound Pb3Mn7O15. Previous analysis based on laboratory X-ray data at room temperature gave contradictory results in terms of the description of the unit cell. Motivated by recent magnetic bulk measurements of this system, we re-investigated the chemical structure with high-resolution synchrotron powder diffraction at temperatures between 15 K and 295 K. Our results show that the crystal structure of stoichiometric Pb3Mn7O15 has a pronounced 2-dimensional character and can be described in the orthorhombic space group Pnma. 
J. C. E. Rasch, D. V. Sheptyakov, J. Schefer, L. Keller, M. B\"ohm, F.   Gozzo, N. V. Volkov, K. A. Sablina, G. A. Petrakovs...