data_global
_chemical_name_mineral 'Dravite'
loop_
_publ_author_name
'Hamburger G E'
'Buerger M J'
_journal_name_full 'American Mineralogist'
_journal_volume 33
_journal_year 1948
_journal_page_first 532
_journal_page_last 540
_publ_section_title
;
 The structure of tourmaline
;
_database_code_amcsd 45
_chemical_compound_source 'de Kalb, New York, USA'
_chemical_formula_sum 'Na Mg3 Al6 Si6 B3 (O31 H4)'
_cell_length_a 15.951
_cell_length_b 15.951
_cell_length_c 7.24
_cell_angle_alpha 90.0
_cell_angle_beta 90.0
_cell_angle_gamma 120.0
_cell_volume 1595.31
_exptl_crystal_density_diffrn  2.994
_symmetry_space_group_name_H-M 'R 3 m'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '2/3+x,1/3+y,1/3+z'
  '1/3+x,2/3+y,2/3+z'
  'x,x-y,z'
  '2/3+x,1/3+x-y,1/3+z'
  '1/3+x,2/3+x-y,2/3+z'
  '-y,-x,z'
  '2/3-y,1/3-x,1/3+z'
  '1/3-y,2/3-x,2/3+z'
  '-x+y,y,z'
  '2/3-x+y,1/3+y,1/3+z'
  '1/3-x+y,2/3+y,2/3+z'
  '-y,x-y,z'
  '2/3-y,1/3+x-y,1/3+z'
  '1/3-y,2/3+x-y,2/3+z'
  '-x+y,-x,z'
  '2/3-x+y,1/3-x,1/3+z'
  '1/3-x+y,2/3-x,2/3+z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
NaX   0.0  0.0  0.77
MgY   0.133  0.0665  0.255
AlZ   0.05  0.367  0.825
SiT   0.192  0.192  0.624
B   0.117  0.234  0.0
O-H1   0.0  0.0  0.403
O2   0.058  0.116  0.0
O-H3   0.233  0.1165  0.032
O4   0.142  0.071  0.624
O5   0.102  0.204  0.742
O6   0.2  0.2  0.403
O7   0.279  0.246  0.758
O8   0.058  0.292  0.0