data_global _chemical_name_mineral 'Tweddillite' loop_ _publ_author_name 'Armbruster T' 'Gnos E' 'Dixon R' 'Gutzmer J' 'Hejny C' 'Dobelin N' 'Medenbach O' _journal_name_full 'Mineralogical Magazine' _journal_volume 66 _journal_year 2002 _journal_page_first 137 _journal_page_last 150 _publ_section_title ; Manganvesuvianite and tweddillite, two new Mn3+-silicate minerals from the Kalahari manganese fields, South Africa ; _database_code_amcsd 0014561 _chemical_compound_source 'Kalahari manganese fields, South Africa' _chemical_formula_sum 'Ca Sr Al1.43 Mn1.313 Fe.257 Si3 O13 H' _cell_length_a 8.934 _cell_length_b 5.718 _cell_length_c 10.325 _cell_angle_alpha 90 _cell_angle_beta 114.54 _cell_angle_gamma 90 _cell_volume 479.805 _exptl_crystal_density_diffrn 3.779 _symmetry_space_group_name_H-M 'P 1 21/m 1' loop_ _space_group_symop_operation_xyz 'x,y,z' 'x,1/2-y,z' '-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 CaA1 0.76460 0.75000 0.15750 1.00000 0.01165 SrA2 0.59410 0.75000 0.42163 1.00000 0.01305 AlM1 0.00000 0.00000 0.00000 0.43000 0.00811 Mn3+M1 0.00000 0.00000 0.00000 0.48000 0.00811 Fe3+M1 0.00000 0.00000 0.00000 0.09000 0.00811 AlM2 0.00000 0.00000 0.50000 1.00000 0.00836 Mn3+M3 0.29540 0.25000 0.21810 0.83333 0.01140 Fe3+M3 0.29540 0.25000 0.21810 0.16667 0.01140 Si1 0.34170 0.75000 0.04110 1.00000 0.01203 Si2 0.68770 0.25000 0.27870 1.00000 0.01077 Si3 0.18030 0.75000 0.31500 1.00000 0.01089 O1 0.23890 0.99150 0.03860 1.00000 0.01798 O2 0.29840 0.97860 0.34800 1.00000 0.01444 O3 0.79670 0.01600 0.34330 1.00000 0.01482 O4 0.06000 0.25000 0.13120 1.00000 0.01140 O5 0.03690 0.75000 0.14790 1.00000 0.01267 O6 0.06610 0.75000 0.40610 1.00000 0.01267 O7 0.51740 0.75000 0.16910 1.00000 0.01773 O8 0.52770 0.25000 0.31100 1.00000 0.01267 O9 0.63230 0.25000 0.10630 1.00000 0.02280 O10 0.08150 0.25000 0.42930 1.00000 0.01140 H10 0.06000 0.25000 0.33900 1.00000 0.05003