AM_Serandite_3 Formula: Na Mn1.924 Si3 H O9 Name: Serandite Unit cell: 7.7163 6.9116 6.7368 90.465 94.037 102.844 , V=349.32 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: neutron