AM_Birnessite_1 Formula: Mn O2.85 Mg.144 H.6 Name: Birnessite Unit cell: 5.05 2.846 7.054 90.0 96.63 90.0 , V=100.70 Space group: C12/M1 (12)

Post J E , Veblen D R , American Mineralogist , 75 (1990) p.477-489, Crystal structure determinations of synthetic sodium, magnesium and potassium, birnessite using TEM and the Rietveld method, Sample: Mg-birn