data_global _amcsd_formula_title 'Na2Mg6Si8O22(OH)2' loop_ _publ_author_name 'Camara F' 'Oberti R' 'Iezzi G' 'Della Ventura G' _journal_name_full 'Physics and Chemistry of Minerals' _journal_volume 30 _journal_year 2003 _journal_page_first 570 _journal_page_last 581 _publ_section_title ; The P2_1/m - C2/m phase transition in synthetic amphibole Na NaMg Mg5 Si8 O22 (OH)2: thermodynamic and crystal-chemical evaluation Sample: T = 270 C ; _database_code_amcsd 0008834 _chemical_formula_sum 'Na1.62 Mg6.19 Si8 O24 H2' _cell_length_a 9.723 _cell_length_b 18.027 _cell_length_c 5.301 _cell_angle_alpha 90 _cell_angle_beta 102.26 _cell_angle_gamma 90 _cell_volume 907.951 _exptl_crystal_density_diffrn 2.920 _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 NaA 0.00000 0.50000 0.00000 0.31000 0.02875 NaAm 0.02590 0.50000 0.09140 0.25000 0.03496 Mg1 0.00000 0.08830 0.50000 1.00000 0.01077 Mg2 0.00000 0.17950 0.00000 1.00000 0.01406 Mg3 0.00000 0.00000 0.00000 1.00000 0.01102 Mg4 0.00000 0.26200 0.50000 0.59500 0.03217 Na4 0.00000 0.26200 0.50000 0.40500 0.03217 Si1 0.28100 0.08500 0.27590 1.00000 0.00823 Si2 0.29240 0.17070 0.78330 1.00000 0.01064 O1 0.11260 0.08630 0.21170 1.00000 0.01089 O2 0.12210 0.17180 0.71910 1.00000 0.01444 O3 0.10880 0.00000 0.70580 1.00000 0.01393 O4 0.37140 0.24690 0.77980 1.00000 0.02280 O5 0.34670 0.12660 0.05880 1.00000 0.01976 O6 0.34560 0.11910 0.55910 1.00000 0.02153 O7 0.33930 0.00000 0.27820 1.00000 0.02077 H 0.19500 0.00000 0.76700 1.00000 0.00013 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 NaA 0.01235 0.06750 0.00367 0.00000 -0.00549 0.00000 NaAm 0.02287 0.05927 0.02896 0.00000 0.01770 0.00000 Mg1 0.01418 0.01646 0.00299 0.00000 0.00499 0.00000 Mg2 0.01738 0.00988 0.01550 0.00000 0.00549 0.00000 Mg3 0.00777 0.00659 0.01590 0.00000 -0.00324 0.00000 Mg4 0.03567 0.04939 0.01808 0.00000 0.02119 0.00000 Na4 0.03567 0.04939 0.01808 0.00000 0.02119 0.00000 Si1 0.01143 0.00823 0.00517 0.00174 0.00349 0.00000 Si2 0.01052 0.01152 0.01020 -0.00174 0.00224 0.00142 O1 0.00732 0.01482 0.01088 -0.00260 0.00299 0.00047 O2 0.01875 0.01811 0.00748 -0.00347 0.00474 0.00047 O3 0.01372 0.01152 0.01618 0.00000 0.00349 0.00000 O4 0.02378 0.01811 0.02202 -0.01041 -0.00474 0.00189 O5 0.01738 0.02963 0.01427 0.00087 0.00698 0.01135 O6 0.01463 0.03951 0.00788 0.00521 -0.00175 -0.01372 O7 0.02698 0.00659 0.03127 0.00000 0.01222 0.00000