data_global _chemical_name_mineral 'Johannsenite' loop_ _publ_author_name 'Freed R L' 'Peacor D R' _journal_name_full 'American Mineralogist' _journal_volume 52 _journal_year 1967 _journal_page_first 709 _journal_page_last 720 _publ_section_title ; Refinement of the crystal structure of johannsenite ; _database_code_amcsd 0000156 _chemical_formula_sum 'Ca Mn Si2 O6' _cell_length_a 9.978 _cell_length_b 9.156 _cell_length_c 5.293 _cell_angle_alpha 90 _cell_angle_beta 105.48 _cell_angle_gamma 90 _cell_volume 466.019 _exptl_crystal_density_diffrn 3.523 _symmetry_space_group_name_H-M 'C 1 2/c 1' loop_ _space_group_symop_operation_xyz 'x,y,z' '1/2+x,1/2+y,z' 'x,-y,1/2+z' '1/2+x,1/2-y,1/2+z' '-x,y,1/2-z' '1/2-x,1/2+y,1/2-z' '-x,-y,-z' '1/2-x,1/2-y,-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_U_iso_or_equiv Ca 0.00000 0.69810 0.75000 0.00735 Mn 0.00000 0.09470 0.75000 0.00608 Si 0.21290 0.40830 0.76370 0.00329 O1 0.37970 0.40700 0.84590 0.00494 O2 0.13680 0.25690 0.67050 0.00595 O3 0.15180 0.47940 0.00430 0.00507