data_global _chemical_name_mineral 'Boron' loop_ _publ_author_name 'Oganov A R' 'Chen J' 'Gatti C' 'Ma Y' 'Ma Y' 'Glass C W' 'Liu Z' 'Yu T' 'Kurakevych O O' 'Solozhenko V L' _journal_name_full 'Nature' _journal_volume 457 _journal_year 2009 _journal_page_first 863 _journal_page_last 867 _publ_section_title ; Ionic high-pressure form of elemental boron Note: theoretical calculation ; _database_code_amcsd 0014681 _chemical_formula_sum 'B7' _cell_length_a 5.054 _cell_length_b 5.620 _cell_length_c 6.987 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 90 _cell_volume 198.455 _exptl_crystal_density_diffrn 2.533 _symmetry_space_group_name_H-M 'P n n m' loop_ _space_group_symop_operation_xyz 'x,y,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,1/2+z' '1/2+x,1/2-y,1/2-z' 'x,y,-z' '-x,-y,z' '-x,-y,-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z B1 0.17020 0.52060 0.00000 B2 0.16060 0.28100 0.37430 B3 0.34720 0.09240 0.20930 B4 0.35200 0.27110 0.00000 B5 0.16440 0.00800 0.00000