Rietveld refinement using synchrotron powder X-ray diffraction data revealed that the crystal structure of synthetic Na-birnessite is triclinic (C1̄), not monoclinic as was previously reported. The Mn-O octahedra have elongated axial bonds, consistent with Jahn-Teller distortion resulting from partial occupancy by Mn3+. Mean Mn-O distances indicate that Mn sites are ∼2/3 Mn4+ and ∼1/3 Mn3+. The interlayer Na cations and H2O molecules occupy a split site that shows evidence of considerable disorder.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics