data_global
_amcsd_formula_title 'Na2SiSi2O7'
loop_
_publ_author_name
'Fleet M E'
'Henderson G S'
_journal_name_full 'Physics and Chemistry of Minerals'
_journal_volume 22 
_journal_year 1995
_journal_page_first 383
_journal_page_last 386
_publ_section_title
;
 Soidium trisilicate: A new high-pressure silicate structure (Na2Si[Si2O7])
;
_database_code_amcsd 0007927
_chemical_formula_sum 'Si3 Na2 O7'
_cell_length_a 8.922
_cell_length_b 4.8490
_cell_length_c 11.567
_cell_angle_alpha 90
_cell_angle_beta 102.64
_cell_angle_gamma 90
_cell_volume 488.293
_exptl_crystal_density_diffrn      3.295
_symmetry_space_group_name_H-M 'C 1 2/c 1'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '1/2+x,1/2+y,z'
  'x,-y,1/2+z'
  '1/2+x,1/2-y,1/2+z'
  '-x,y,1/2-z'
  '1/2-x,1/2+y,1/2-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
Si1   0.45777   0.28452   0.11515
Si2   0.25000   0.25000   0.50000
Na   0.14770   0.29478   0.18326
O1   0.36080   0.56388   0.12681
O2   0.36502   0.04726   0.03572
O3   0.37597   0.36728   0.41000
O4   0.00000   0.64740   0.25000
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 0.00545 0.00303 0.00497 -0.00002 0.00105 -0.00025
Si2 0.00538 0.00304 0.00510 -0.00002 0.00114 0.00025
Na 0.02100 0.00825 0.02427 -0.00049 0.01075 -0.00194
O1 0.00810 0.00440 0.00652 0.00150 0.00075 -0.00008
O2 0.00779 0.00418 0.00904 -0.00148 0.00114 -0.00139
O3 0.00695 0.00621 0.00878 0.00051 0.00304 0.00186
O4 0.01386 0.00516 0.00581 0.00000 0.00129 0.00000