AM_Eckermannite Formula: O22 F2 Si8 Mg4.094 Sc.906 Na3 Name: Eckermannite Unit cell: 9.8384 18.0634 5.2926 90.0 103.65 90.0 , V=914.01 Space group: C12/M1 (12)

Raudsepp M , Turnock A C , Hawthorne F C , American Mineralogist , 72 (1987) p.959-964, Characterization of cation ordering in synthetic scandium-fluor-eckermannite,, indium-fluor-eckermannite, and scandium-fluor-nyboite by Rietveld structure, refinement, Sample: FScEC-A3