data_global _chemical_name_mineral 'Heulandite-Ca' loop_ _publ_author_name 'Gunter M E' 'Armbruster T' 'Kohler T' 'Knowles C R' _journal_name_full 'American Mineralogist' _journal_volume 79 _journal_year 1994 _journal_page_first 675 _journal_page_last 682 _publ_section_title ; Crystal structure and optical properties of Na- and Pb-exchanged heulandite-group zeolites Sample: nonexchanged Atomic parameters from ICSD ; _database_code_amcsd 0001668 _chemical_formula_sum 'Na.65 Ca1.848 K.06 (Si13.554 Al4.446) O48.38 H12.38' _cell_length_a 17.671 _cell_length_b 17.875 _cell_length_c 7.412 _cell_angle_alpha 90 _cell_angle_beta 116.39 _cell_angle_gamma 90 _cell_volume 2097.242 _exptl_crystal_density_diffrn 2.183 _symmetry_space_group_name_H-M 'C 1 2/m 1' loop_ _space_group_symop_operation_xyz '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' '-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_U_iso_or_equiv Na1 0.15490 0.00000 0.66660 0.22800 0.07979 Ca1 0.15490 0.00000 0.66660 0.44000 0.07979 Ca2 0.54020 0.00000 0.20310 0.48400 0.03470 K 0.27630 0.00000 0.01000 0.03000 0.12538 Na2 0.27630 0.00000 0.01000 0.09700 0.12538 Si1 0.17940 0.16980 0.09670 0.75300 0.01697 Al1 0.17940 0.16980 0.09670 0.24700 0.01697 Si2 0.28860 0.08990 0.50080 0.75300 0.01798 Al2 0.28860 0.08990 0.50080 0.24700 0.01798 Si3 0.29170 0.30960 0.28310 0.75300 0.01710 Al3 0.29170 0.30960 0.28310 0.24700 0.01710 Si4 0.06460 0.29840 0.41100 0.75300 0.01697 Al4 0.06460 0.29840 0.41100 0.24700 0.01697 Si5 0.00000 0.21310 0.00000 0.75300 0.01773 Al5 0.00000 0.21310 0.00000 0.24700 0.01773 O1 0.30480 0.00000 0.54660 1.00000 0.03546 O2 0.23130 0.11940 0.61320 1.00000 0.03863 O3 0.18330 0.15430 0.88420 1.00000 0.04078 O4 0.23850 0.10650 0.25550 1.00000 0.03103 O5 0.00000 0.32590 0.50000 1.00000 0.04306 O6 0.08200 0.15870 0.06260 1.00000 0.02812 O7 0.37290 0.26600 0.45080 1.00000 0.04129 O8 0.00890 0.26620 0.18420 1.00000 0.03521 O9 0.21030 0.25420 0.17830 1.00000 0.03344 O10 0.11550 0.37230 0.39880 1.00000 0.03344 O-H11 0.27630 0.00000 0.01000 0.83000 0.12538 O-H12 0.50000 0.00000 0.50000 1.00000 0.10005 O-H13 0.42280 0.08170 0.03070 1.00000 0.06839 O-H14 0.09400 0.00000 0.28500 1.00000 0.16718 O-H15 0.08200 0.00500 0.86700 0.43000 0.14996 O-H16 0.00000 0.08730 0.50000 1.00000 0.25964