AM_Ferrocolumbite_6 Formula: Fe.264 Mn.07 Nb.633 Ta.034 O2 Name: Ferrocolumbite Unit cell: 14.26 5.7293 5.0746 90.0 90.0 90.0 , V=414.59 Space group: PBCN (60)

Tarantino S C , Zema M , American Mineralogist , 90 (2005) p.1291-1300, Mixing and ordering behavior in manganocolumbite-ferrocolumbite solid solution:, A single-crystal X-ray diffraction study, Sample: BRA n18 Qm=0.752 from S. Jose de Safira, Minas Gerais, Brazil, Sample: Annealed at T = 700 C for t = 5 m, Note: Occupancies calculated assuming complete Fe/Mn disorder