Serandite_2 Formula: Na Mn1.933 Si3 H O9 Name: Serandite Unit cell: 7.7185 6.9064 6.7624 90.492 94.085 102.775 , V=350.56 Space group: P-1 (2)
Jacobsen S D , Smyth J R , Swope R J , Sheldon R I , American Mineralogist , 85 (2000) p.745-752, Two proton positions in the very strong hydrogen bond of serandite,, NaMn2[Si3O8(OH)], Sample: X-ray