AM_Ilvaite_33 Formula: Fe3 Ca Si2 O9 H Name: Ilvaite Unit cell: 13.0466 8.8268 5.8647 90.0 90.124 90.0 , V=675.38 Space group: P121/A1 (14)

Ghose S , Tsukimura K , Hatch D M , Physics and Chemistry of Minerals , 16 (1989) p.483-496, Phase transitions in ilvaite, a mixed-valence iron silicate, II. A single-crystal X-ray diffraction study and Landau theory of the, monoclinic to orthorhombic phase transition induced by charge delocalization, Sample: T = 340 K