AM_Birnessite_4 Formula: Na.29 Mn O2.691 H4 Name: Birnessite Unit cell: 5.178 2.8509 7.3344 89.45 103.18 89.91 , V=105.41 Space group: C-1 (2)

Lopano C L , Heaney P J , Post J E , Hanson J , Komarneni S , American Mineralogist , 92 (2007) p.380-387, Time-resolved structural analysis of K-and Ba-exchange reactions with synthetic, Na-birnessite using synchrotron X-ray diffraction, Locality: synthetic, Sample: Na-birnessite