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 = 140 C ; _database_code_amcsd 0008833 _chemical_formula_sum 'Na1.62 Mg6.19 Si8 O24 H2' _cell_length_a 9.706 _cell_length_b 17.986 _cell_length_c 5.286 _cell_angle_alpha 90 _cell_angle_beta 102.37 _cell_angle_gamma 90 _cell_volume 901.365 _exptl_crystal_density_diffrn 2.942 _symmetry_space_group_name_H-M 'P 1 21/m 1' loop_ _space_group_symop_operation_xyz 'x,y,z' 'x,1/2-y,z' '-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_occupancy _atom_site_U_iso_or_equiv NaA 0.27070 0.25000 0.04440 0.81000 0.04851 Mg1 -0.24850 0.33820 0.49080 1.00000 0.00811 Mg2 -0.25030 0.42960 0.98290 1.00000 0.00823 Mg3 -0.25330 0.25000 0.98980 1.00000 0.00773 Mg4 -0.24060 0.50590 0.49250 0.59500 0.01013 Na4* -0.25930 0.52280 0.47100 0.40500 0.01849 Si1A 0.03230 0.33590 0.26450 1.00000 0.00633 Si1B 0.53060 0.83430 0.28940 1.00000 0.00621 Si2A 0.04010 0.42160 0.77220 1.00000 0.00659 Si2B 0.54460 0.91950 0.79630 1.00000 0.00760 O1A -0.13880 0.33570 0.19570 1.00000 0.00747 O1B -0.12780 0.42110 0.71260 1.00000 0.00735 O2A 0.36510 0.83700 0.22780 1.00000 0.00912 O2B 0.37010 0.92160 0.72630 1.00000 0.00975 O-H3A -0.13610 0.25000 0.69830 1.00000 0.00861 O-H3B 0.35510 0.75000 0.72360 1.00000 0.00899 O4A 0.12460 0.49860 0.78910 1.00000 0.01368 O4B 0.62040 0.99470 0.77240 1.00000 0.02356 O5A 0.09610 0.36920 0.03190 1.00000 0.01203 O5B 0.59870 0.88330 0.08780 1.00000 0.01140 O6A 0.09850 0.37770 0.53570 1.00000 0.01267 O6B 0.59430 0.85860 0.58770 1.00000 0.01279 O7A 0.09420 0.25000 0.30010 1.00000 0.01089 O7B 0.58690 0.75000 0.26080 1.00000 0.01102 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 0.02869 0.07211 0.05591 0.00000 0.03224 0.00000 Mg1 0.01047 0.00819 0.00648 0.00000 0.00198 -0.00047 Mg2 0.00956 0.00656 0.00851 0.00000 0.00248 0.00094 Mg3 0.00956 0.00656 0.00675 0.00000 0.00099 0.00000 Mg4 0.01093 0.01147 0.00972 0.00000 0.00670 0.00094 Si1A 0.00774 0.00656 0.00581 -0.00086 0.00124 -0.00047 Si1B 0.00774 0.00656 0.00500 0.00000 0.00149 0.00047 Si2A 0.00774 0.00656 0.00554 -0.00086 0.00124 -0.00047 Si2B 0.00911 0.00819 0.00621 -0.00259 0.00099 0.00094 O1A 0.00865 0.00819 0.00648 -0.00086 0.00174 -0.00094 O1B 0.00820 0.00819 0.00621 0.00000 0.00149 0.00000 O2A 0.00820 0.01147 0.00837 -0.00086 0.00248 -0.00235 O2B 0.01138 0.01147 0.00675 -0.00086 0.00198 -0.00141 O-H3A 0.01002 0.00819 0.00783 0.00000 0.00174 0.00000 O-H3B 0.00774 0.00983 0.00959 0.00000 0.00223 0.00000 O4A 0.01912 0.00819 0.01256 -0.00518 -0.00174 -0.00094 O4B 0.03005 0.01803 0.01715 -0.01469 -0.00967 0.00847 O5A 0.01093 0.01639 0.00999 0.00086 0.00322 0.00565 O5B 0.01047 0.01311 0.01026 -0.00173 0.00223 0.00423 O6A 0.01047 0.01639 0.01107 0.00259 0.00000 -0.00800 O6B 0.01047 0.01967 0.00797 0.00173 0.00074 -0.00518 O7A 0.01093 0.00656 0.01567 0.00000 0.00298 0.00000 O7B 0.00956 0.00656 0.01837 0.00000 0.00471 0.00000