AM_Birnessite_5 Formula: K.23 Mn O2.776 H4 Name: Birnessite Unit cell: 5.1371 2.8476 7.2131 89.96 100.75 89.702 , V=103.66 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: K-birnessite