data_global _amcsd_formula_title 'Na1.8Ca1.1Si6O14' loop_ _publ_author_name 'Gasparik T' 'Parise J B' 'Eiben B A' 'Hriljac J A' _journal_name_full 'American Mineralogist' _journal_volume 80 _journal_year 1995 _journal_page_first 1269 _journal_page_last 1276 _publ_section_title ; Stability and structure of a new high-pressure silicate, Na1.8Ca1.1Si6O14 Sample: data collected on a diffractometer Note: U(2,3) for Si2, Na/Ca altered to match symmetry constraints. ; _database_code_amcsd 0001761 _chemical_formula_sum 'Si6 Na1.8 Ca1.11 O14' _cell_length_a 7.903 _cell_length_b 7.903 _cell_length_c 4.595 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 120 _cell_volume 248.542 _exptl_crystal_density_diffrn 3.196 _symmetry_space_group_name_H-M 'P 3 2 1' loop_ _space_group_symop_operation_xyz 'x,y,z' 'y,x,-z' '-y,x-y,z' '-x,-x+y,-z' '-x+y,-x,z' 'x-y,-y,-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_occupancy Si1 0.66667 0.33333 0.48990 1.00000 Si2 0.74751 0.74751 0.50000 1.00000 Si3 0.00000 0.00000 0.00000 1.00000 Na 0.41485 0.41485 0.00000 0.60000 Ca 0.41485 0.41485 0.00000 0.37000 O1 0.70210 0.53940 0.35050 1.00000 O2 0.66667 0.33333 0.82880 1.00000 O3 0.89630 0.78990 0.76840 1.00000 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 Si1 0.00550 0.00550 0.00560 0.00275 0.00000 0.00000 Si2 0.00500 0.00500 0.00400 0.00250 -0.00030 0.00030 Si3 0.00540 0.00540 0.00330 0.00270 0.00000 0.00000 Na 0.01070 0.01070 0.00930 0.00400 0.00050 -0.00050 Ca 0.01070 0.01070 0.00930 0.00400 0.00050 -0.00050 O1 0.01780 0.00670 0.00810 0.00650 -0.00270 -0.00110 O2 0.02060 0.02060 0.00590 0.01030 0.00000 0.00000 O3 0.00730 0.00690 0.00530 0.00390 -0.00210 -0.00110