data_global _chemical_name_mineral 'Sederholmite' loop_ _publ_author_name 'Alsen N' _journal_name_full 'Geologiska Foreningens i Stockholm Forhandlingar' _journal_volume 47 _journal_year 1925 _journal_page_first 19 _journal_page_last 73 _publ_section_title ; Roentgenographische Untersuchungen der Kristallstrukturen von Magnetkies, Breithauptit, Pentlandit, Millerit und verwandten Verbindungen _cod_database_code 1011367 ; _database_code_amcsd 0018201 _chemical_formula_sum 'Ni Se' _cell_length_a 3.66 _cell_length_b 3.66 _cell_length_c 5.33 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 120 _cell_volume 61.833 _exptl_crystal_density_diffrn 7.393 _symmetry_space_group_name_H-M 'P 63/m m c' loop_ _space_group_symop_operation_xyz 'x,y,z' '-x,-x+y,1/2+z' 'x,x-y,1/2-z' '-x+y,-x,1/2-z' 'x-y,x,1/2+z' '-y,-x,z' 'y,x,-z' 'y,-x+y,-z' '-y,x-y,z' 'x-y,-y,1/2+z' '-x+y,y,1/2-z' 'x,y,1/2-z' '-x,-y,1/2+z' 'x,x-y,z' '-x,-x+y,-z' 'x-y,x,-z' '-x+y,-x,z' 'y,x,1/2+z' '-y,-x,1/2-z' '-y,x-y,1/2-z' 'y,-x+y,1/2+z' '-x+y,y,z' 'x-y,-y,-z' '-x,-y,-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z Ni1 0.00000 0.00000 0.00000 Se1 0.33333 0.66667 0.25000