AM_Weberite_1 Formula: Na2 Mg Al F7 Name: Weberite Unit cell: 7.051 9.968 7.285 90.0 90.0 90.0 , V=512.02 Space group: IMMA (74)

Knop O , Cameron T S , Jochem K , Journal of Solid State Chemistry , 43 (1982) p.213-221, What is the true space group of weberite?, Locality: Ivigtut, Greenland, Sample: Imma refinement, T = ambient