data_global
_chemical_name_mineral 'Dravite'
loop_
_publ_author_name
'Grice J D'
'Ercit T S'
_journal_name_full 'Neues Jahrbuch fur Mineralogie, Abhandlungen'
_journal_volume 165 
_journal_year 1993
_journal_page_first 245
_journal_page_last 266
_publ_section_title
;
 Ordering of Fe and Mg in the tourmaline crystal structure: The correct formula
 Sample: Dravite 43167
;
_database_code_amcsd 0018789
_chemical_compound_source 'Moctezuma, Sonora, Mexico'
_chemical_formula_sum 'Na.77 Ca.18 Mg1.86 Al5.47 Fe1.67 Si5.78 B3.17 Ti.05 O31 H3.6'
_cell_length_a 15.960
_cell_length_b 15.960
_cell_length_c 7.238
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 120
_cell_volume 1596.669
_exptl_crystal_density_diffrn      3.150
_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
_atom_site_occupancy
_atom_site_U_iso_or_equiv
NaX   0.00000   0.00000   0.23660   0.77000   0.02410
CaX   0.00000   0.00000   0.23660   0.18000   0.02410
MgY   0.12392   0.06196   0.63460   0.46670   0.00710
AlY   0.12392   0.06196   0.63460   0.14000   0.00710
Fe2Y   0.12392   0.06196   0.63460   0.07000   0.00710
Fe3Y   0.12392   0.06196   0.63460   0.32330   0.00710
AlZ   0.29810   0.26164   0.61220   0.84170   0.00620
FeZ   0.29810   0.26164   0.61220   0.08170   0.00620
MgZ   0.29810   0.26164   0.61220   0.07670   0.00620
SiT   0.19154   0.18981   0.00000   0.96330   0.00600
BT   0.19154   0.18981   0.00000   0.02830   0.00600
TiT   0.19154   0.18981   0.00000   0.00830   0.00600
B   0.10990   0.21980   0.45490   1.00000   0.00900
O-H1   0.00000   0.00000   0.77300   0.60000   0.01780
O1   0.00000   0.00000   0.77300   0.40000   0.01780
O2   0.06130   0.12260   0.48610   1.00000   0.01280
O3   0.26360   0.13180   0.51260   1.00000   0.01370
O4   0.09300   0.18600   0.06960   1.00000   0.01210
O5   0.18400   0.09200   0.09040   1.00000   0.01100
O6   0.19570   0.18580   0.77830   1.00000   0.01000
O7   0.28460   0.28460   0.07910   1.00000   0.01030
O8   0.20920   0.26950   0.44160   1.00000   0.01170
H3   0.25400   0.12700   0.40100   1.00000   0.01500