data_9000145 _chemical_name 'Cordierite' loop_ _publ_author_name 'Gibbs G V' _journal_name_full "American Mineralogist" _journal_volume 51 _journal_year 1966 _journal_page_first 1068 _journal_page_last 1087 _publ_section_title ; The polymorphism of cordierite I: The crystal structure of low cordierite ; _chemical_formula_sum 'Al4 Si5 (Mg1.54 Fe.46) O18.48 Li.12 Na.1 Ca.03 K.02 H2' _cell_length_a 17.083 _cell_length_b 9.738 _cell_length_c 9.335 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 90 _cell_volume 1552.917 _symmetry_space_group_name_H-M 'C c c m' loop_ _symmetry_equiv_pos_as_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,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' '-x,-y,z' '1/2-x,1/2-y,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_occupancy _atom_site_Uiso_or_equiv Al1 0.25000 0.25000 0.25000 1.00000 0.00279 Si2 0.00000 0.50000 0.25000 0.92000 0.00253 Al2 0.00000 0.50000 0.25000 0.08000 0.00253 Si3 0.19230 0.07810 0.00000 1.00000 0.00329 Si4 0.13510 -0.23720 0.00000 1.00000 0.00291 Al5 0.05060 0.30840 0.00000 0.96000 0.00317 Si5 0.05060 0.30840 0.00000 0.04000 0.00317 Mg 0.33740 0.00000 0.25000 0.77000 0.00291 Fe 0.33740 0.00000 0.25000 0.23000 0.00291 O1 0.24660 -0.10400 0.35910 1.00000 0.00342 O2 0.06160 -0.41670 0.34940 1.00000 0.00304 O3 -0.17300 -0.30910 0.35830 1.00000 0.00393 O4 0.04340 -0.24530 0.00000 1.00000 0.00317 O5 0.12240 0.18480 0.00000 1.00000 0.00823 O6 0.16390 -0.07880 0.00000 1.00000 0.00684 Wat 0.00000 0.00000 0.25000 0.48000 0.09030 Li 0.00000 0.00000 0.25000 0.12000 0.09030 Na 0.00000 0.00000 0.25000 0.10000 0.09030 Ca 0.00000 0.00000 0.25000 0.03000 0.09030 K 0.00000 0.00000 0.25000 0.02000 0.09030