data_global _chemical_name_mineral 'Tephroite' loop_ _publ_author_name 'Redfern S A T' 'Knight K S' 'Henderson C M B' 'Wood B J' _journal_name_full 'Mineralogical Magazine' _journal_volume 62 _journal_year 1998 _journal_page_first 607 _journal_page_last 615 _publ_section_title ; Fe-Mn cation ordering in fayalite-tephroite (FexMn1-x)2SiO4 olivines: A neutron diffraction study ; _database_code_amcsd 0019697 _chemical_compound_source 'Synthetic' _chemical_formula_sum '(Mn Fe) Si O4' _cell_length_a 4.86184 _cell_length_b 10.58358 _cell_length_c 6.16950 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 90 _cell_volume 317.456 _exptl_crystal_density_diffrn 4.245 _symmetry_space_group_name_H-M 'P b n m' loop_ _space_group_symop_operation_xyz 'x,y,z' 'x,y,1/2-z' '-x,-y,1/2+z' '1/2+x,1/2-y,1/2+z' '1/2-x,1/2+y,1/2-z' '1/2-x,1/2+y,z' '1/2+x,1/2-y,-z' '-x,-y,-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_occupancy _atom_site_U_iso_or_equiv MnM1 0.00000 0.00000 0.00000 0.33400 0.00519 FeM1 0.00000 0.00000 0.00000 0.66600 0.00519 MnM2 0.97860 0.28240 0.25000 0.66600 0.00519 FeM2 0.97860 0.28240 0.25000 0.33400 0.00519 Si 0.42810 0.09610 0.25000 1.00000 0.00456 O1 0.76360 0.09220 0.25000 1.00000 0.00785 O2 0.21320 0.45360 0.25000 1.00000 0.00760 O3 0.28760 0.16380 0.03840 1.00000 0.00747