data_global
_chemical_name_mineral 'Cryolite'
loop_
_publ_author_name
'Yang H'
'Ghose S'
'Hatch D M'
_journal_name_full 'Physics and Chemistry of Minerals'
_journal_volume 19 
_journal_year 1993
_journal_page_first 528
_journal_page_last 544
_publ_section_title
;
 Ferroelastic phase transition in cryolite, Na3AlF6, a mixed
 fluoride perovskite: high temperature single crystal X-ray
 diffraction study and symmetry analysis of the transition mechanism
 Sample: T = 800 K
;
_database_code_amcsd 0007744
_chemical_formula_sum 'Al Na3 F6'
_cell_length_a 5.5395
_cell_length_b 5.6378
_cell_length_c 7.9085
_cell_angle_alpha 90
_cell_angle_beta 90.011
_cell_angle_gamma 90
_cell_volume 246.987
_exptl_crystal_density_diffrn      2.823
_symmetry_space_group_name_H-M 'P 1 21/n 1'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '1/2+x,1/2-y,1/2+z'
  '1/2-x,1/2+y,1/2-z'
  '-x,-y,-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
Al   0.00000   0.00000   0.00000
Na1   0.00000   0.00000   0.50000
Na2  -0.00750   0.46450   0.25100
F1   0.08880   0.03420   0.21790
F2   0.23350   0.32500   0.53990
F3   0.16790   0.26460   0.94760
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
Al 0.03793 0.03753 0.06942 0.00070 -0.00009 0.00061
Na1 0.06675 0.06509 0.12161 -0.00932 -0.00206 0.00298
Na2 0.09674 0.09650 0.19978 -0.01147 0.00129 0.00346
F1 0.10789 0.13730 0.08675 0.00263 -0.02137 -0.01782
F2 0.07487 0.08156 0.20139 -0.03468 0.02197 -0.00768
F3 0.08547 0.06806 0.25187 -0.02565 0.00590 0.03519