data_global _chemical_name_mineral 'Heulandite-Ca' loop_ _publ_author_name 'Merkle A B' 'Slaughter M' _journal_name_full 'American Mineralogist' _journal_volume 52 _journal_year 1967 _journal_page_first 273 _journal_page_last 276 _publ_section_title ; The crystal structure of heulandite (Ca,Na2)[Al2Si7O18].6H2O ; _database_code_amcsd 154 _chemical_formula_sum 'Ca (Si4.398 Al1.602) O16.002 H8.004' _cell_length_a 17.73 _cell_length_b 17.82 _cell_length_c 7.43 _cell_angle_alpha 90.0 _cell_angle_beta 116.33 _cell_angle_gamma 90.0 _cell_volume 2103.955 _exptl_crystal_density_diffrn 2.23 _symmetry_space_group_name_H-M 'C 1 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' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_occupancy Ca1 0.147 0.0 0.811 1.0 Ca2 0.435 0.0 0.147 1.0 Ca3 0.242 0.5 0.3 1.0 Si1 0.109 0.168 0.405 0.733 Al1 0.109 0.168 0.405 0.267 Si2 0.002 0.093 0.0 0.733 Al2 0.002 0.093 0.0 0.267 Si3 0.08 0.184 0.782 0.733 Al3 0.08 0.184 0.782 0.267 Si4 0.342 0.304 0.909 0.733 Al4 0.342 0.304 0.909 0.267 Si5 0.287 0.216 0.5 0.733 Al5 0.287 0.216 0.5 0.267 Si6 0.495 0.198 0.216 0.733 Al6 0.495 0.198 0.216 0.267 Si7 0.468 0.173 0.593 0.733 Al7 0.468 0.173 0.593 0.267 Si8 0.216 0.302 0.086 0.733 Al8 0.216 0.302 0.086 0.267 Si9 0.072 0.415 0.0 0.733 Al9 0.072 0.415 0.0 0.267 O1 0.983 0.0 0.947 1.0 O2 0.061 0.13 0.9 1.0 O3 0.102 0.143 0.605 1.0 O4 0.044 0.122 0.235 1.0 O5 0.292 0.338 0.018 1.0 O6 0.211 0.167 0.428 1.0 O7 0.142 0.256 0.943 1.0 O8 0.295 0.259 0.679 1.0 O9 0.084 0.247 0.314 1.0 O10 0.279 0.283 0.313 1.0 O11 0.37 0.151 0.559 1.0 O12 0.023 0.404 0.753 1.0 O13 0.081 0.5 0.044 1.0 O14 0.463 0.162 0.362 1.0 O15 0.492 0.263 0.663 1.0 O16 0.404 0.376 0.906 1.0 O17 0.02 0.38 0.117 1.0 O18 0.17 0.383 0.109 1.0 O19 0.407 0.233 0.055 1.0 Wat1 0.006 0.0 0.528 0.667 Wat2 0.294 0.5 0.038 0.667 Wat3 0.296 0.5 0.767 0.667 Wat4 0.065 0.5 0.518 0.667 Wat5 0.386 0.0 0.772 0.667 Wat6 0.209 0.0 0.601 0.667 Wat7 0.256 0.137 0.005 0.667 Wat8 0.211 0.423 0.509 0.667 Wat9 0.36 0.424 0.469 0.667 Wat10 0.389 0.0 0.404 0.667 Wat11 0.379 0.0 0.291 0.667 Wat12 0.208 0.0 0.45 0.667 Wat13 0.375 0.0 0.52 0.667 Wat14 0.222 0.172 0.109 0.667