data_global _amcsd_formula_title 'Na(Mg0.5Si0.5)Si2O6' loop_ _publ_author_name 'Angel R J' 'Gasparik T' 'Ross N L' 'Finger L W' 'Prewitt C T' 'Hazen R M' _journal_name_full 'Nature' _journal_volume 335 _journal_year 1988 _journal_page_first 156 _journal_page_last 158 _publ_section_title ; A silica-rich sodium pyroxene phase with six-coordinated silicon ; _database_code_amcsd 0014678 _chemical_compound_source 'Synthetic' _chemical_formula_sum 'Mg Si5 Na2 O12' _cell_length_a 9.418 _cell_length_b 8.647 _cell_length_c 5.274 _cell_angle_alpha 90 _cell_angle_beta 108.13 _cell_angle_gamma 90 _cell_volume 408.178 _exptl_crystal_density_diffrn 3.277 _symmetry_space_group_name_H-M 'P 1 2/n 1' loop_ _space_group_symop_operation_xyz 'x,y,z' '1/2-x,y,1/2-z' '1/2+x,-y,1/2+z' '-x,-y,-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_U_iso_or_equiv MgM1 0.75000 0.65490 0.25000 0.00709 SiM1(1) 0.75000 0.84690 0.75000 0.00507 NaM2 0.75000 0.05130 0.25000 0.01051 NaM2(1) 0.75000 0.45670 0.75000 0.01646 SiT1 0.04470 0.84860 0.22700 0.00494 SiT2 0.03720 0.66520 0.73550 0.00507 O1(1) 0.86200 0.84430 0.10170 0.00633 O1(2) 0.85670 0.69340 0.65620 0.00583 O2(1) 0.12340 0.01460 0.30770 0.00722 O2(2) 0.09820 0.49500 0.79110 0.00861 O3(1) 0.11280 0.76650 0.01190 0.00735 O3(2) 0.09300 0.75270 0.50700 0.00722 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 MgM1 0.00690 0.00833 0.00522 0.00000 0.00114 0.00000 SiM1(1) 0.00609 0.00492 0.00458 0.00000 0.00205 0.00000 NaM2 0.01380 0.00871 0.00764 0.00000 0.00136 0.00000 NaM2(1) 0.02273 0.00947 0.01158 0.00000 -0.00250 0.00000 SiT1 0.00487 0.00530 0.00445 -0.00039 0.00136 -0.00044 SiT2 0.00487 0.00606 0.00496 0.00000 0.00227 0.00022 O1(1) 0.00487 0.00947 0.00484 -0.00039 0.00159 0.00044 O1(2) 0.00487 0.00795 0.00382 0.00078 0.00023 -0.00022 O2(1) 0.00812 0.00682 0.00675 -0.00196 0.00227 -0.00088 O2(2) 0.00893 0.00720 0.00929 0.00196 0.00273 0.00022 O3(1) 0.00609 0.00985 0.00636 -0.00039 0.00205 -0.00263 O3(2) 0.00649 0.00947 0.00547 -0.00078 0.00136 0.00154