data_global
_chemical_name_mineral 'Povondraite'
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: Povondraite 144478
;
_database_code_amcsd 0018783
_chemical_compound_source 'San Francisco mine, Villa Tu nari, Bolivia'
_chemical_formula_sum 'Na.79 K.26 Mg1.85 Fe6.82 V.01 Al.32 Si5.94 B3.06 O31 H3.3'
_cell_length_a 16.186
_cell_length_b 16.186
_cell_length_c 7.444
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 120
_cell_volume 1688.947
_exptl_crystal_density_diffrn      3.429
_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   0.22800   0.79000   0.02730
KX   0.00000   0.00000   0.22800   0.26000   0.02730
MgY   0.12238   0.06119   0.64300   0.01670   0.00640
Fe2Y   0.12238   0.06119   0.64300   0.14330   0.00640
VY   0.12238   0.06119   0.64300   0.00330   0.00640
Fe3Y   0.12238   0.06119   0.64300   0.83670   0.00640
AlZ   0.29870   0.26270   0.61240   0.05330   0.00570
Fe3Z   0.29870   0.26270   0.61240   0.64670   0.00570
MgZ   0.29870   0.26270   0.61240   0.30000   0.00570
SiT   0.18920   0.18760   0.00000   0.99000   0.00610
BT   0.18920   0.18760   0.00000   0.01000   0.00610
B   0.10970   0.21940   0.45600   1.00000   0.00860
O1   0.00000   0.00000   0.77200   0.70000   0.00730
O-H1   0.00000   0.00000   0.77200   0.30000   0.00730
O2   0.06090   0.12180   0.49100   1.00000   0.00940
O3   0.25780   0.12890   0.51300   1.00000   0.00880
O4   0.09240   0.18480   0.06900   1.00000   0.01080
O5   0.18260   0.09130   0.08700   1.00000   0.00990
O6   0.19230   0.18290   0.78400   1.00000   0.00810
O7   0.28100   0.28130   0.07500   1.00000   0.00960
O8   0.20690   0.26780   0.44200   1.00000   0.01010
H3   0.24200   0.12100   0.41000   1.00000   0.01000