Birnessite
Post J E, Veblen D R
American Mineralogist 75 (1990) 477-489
Crystal structure determinations of synthetic sodium, magnesium and potassium
birnessite using TEM and the Rietveld method
Sample: Mg-birn
_database_code_amcsd 0001301
5.050 2.846 7.054 90 96.63 90 C2/m
atom    x y    z  occ Biso
Mn      0 0    0       0.5
O1   .356 0 .141       1.0
Mg   .023 0 .282 .072  0.5
Wat2 .703 0 .506 .425  1.5