data_global _chemical_name_mineral 'Pyroxene-ideal' loop_ _publ_author_name 'Thompson R M' 'Downs R T' _journal_name_full 'American Mineralogist' _journal_volume 89 _journal_year 2004 _journal_page_first 614 _journal_page_last 628 _publ_section_title ; Model pyroxenes II: Structural variation as a function of tetrahedral rotation model spodumene at 760C after Cameron et al. (1973) with O3-O3-O3 angle = 186.6 and model oxygen radius = 1.267 ; _database_code_amcsd 0003488 _chemical_formula_sum 'Al Li Si2 O6' _cell_length_a 9.589 _cell_length_b 8.766 _cell_length_c 5.061 _cell_angle_alpha 90 _cell_angle_beta 111.7 _cell_angle_gamma 90 _cell_volume 395.265 _exptl_crystal_density_diffrn 3.127 _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 Al 0.00000 0.91667 0.25000 Li 0.00000 0.25000 0.25000 Si 0.30810 0.08333 0.29890 O1 0.13390 0.08333 0.17700 O2 0.36610 0.25000 0.32300 O3 0.36610 -0.00830 0.09790