data_global _chemical_name_mineral 'Rankinite' loop_ _publ_author_name 'Saburi S' 'Kusachi I' 'Henmi C' 'Kawahara A' 'Henmi K' 'Kawada I' _journal_name_full 'Mineralogical Journal' _journal_volume 8 _journal_year 1976 _journal_page_first 240 _journal_page_last 246 _publ_section_title ; Refinement of the structure of rankinite ; _database_code_amcsd 0014417 _chemical_formula_sum 'Ca3 Si2 O7' _cell_length_a 10.557 _cell_length_b 8.885 _cell_length_c 7.858 _cell_angle_alpha 90 _cell_angle_beta 119.586 _cell_angle_gamma 90 _cell_volume 640.969 _exptl_crystal_density_diffrn 2.989 _symmetry_space_group_name_H-M 'P 1 21/a 1' loop_ _space_group_symop_operation_xyz 'x,y,z' '1/2+x,1/2-y,z' '1/2-x,1/2+y,-z' '-x,-y,-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_U_iso_or_equiv Ca1 0.00867 0.05871 0.28957 0.03382 Ca2 0.16829 0.57424 0.20934 0.03040 Ca3 0.34078 0.90736 0.28490 0.03128 Si1 0.09055 0.21502 0.98429 0.03040 Si2 0.29602 0.23395 0.43206 0.03014 O1 0.35625 0.39730 0.42113 0.03280 O2 0.17948 0.23873 0.50723 0.03420 O3 0.40989 0.10295 0.54763 0.03445 O4 0.20191 0.15519 0.20980 0.03420 O5 0.09903 0.39489 0.97373 0.03458 O6 0.14429 0.14102 0.84624 0.03432 O7 0.92820 0.16241 0.93207 0.03774 loop_ _atom_site_aniso_label _atom_site_aniso_U_11 _atom_site_aniso_U_22 _atom_site_aniso_U_33 _atom_site_aniso_U_12 _atom_site_aniso_U_13 _atom_site_aniso_U_23 Ca1 0.02835 0.03439 0.03714 -0.02603 0.01503 -0.00169 Ca2 0.02609 0.03071 0.03288 -0.00004 0.01316 -0.00108 Ca3 0.02694 0.03127 0.03399 0.00062 0.01386 0.00077 Si1 0.02716 0.03023 0.03222 -0.00045 0.01348 -0.00043 Si2 0.02605 0.03003 0.03215 -0.00029 0.01262 0.00018 O1 0.02993 0.03163 0.03468 0.00140 0.01405 0.00105 O2 0.02861 0.03567 0.03761 0.00025 0.01576 -0.00028 O3 0.02903 0.03463 0.03742 0.00091 0.01424 0.00289 O4 0.03386 0.02927 0.03733 -0.00079 0.01602 -0.00037 O5 0.02997 0.03183 0.03697 -0.00021 0.01262 -0.00034 O6 0.02912 0.03447 0.03671 0.00124 0.01402 -0.00120 O7 0.03040 0.03215 0.04831 0.00029 0.01764 0.00298