data_9001996
_chemical_name 'Fluoro-eckermannite'
loop_
_publ_author_name
'Oberti R'
'Hawthorne F C'
'Camara F'
'Raudsepp M'
_journal_name_full "American Mineralogist"
_journal_volume 84
_journal_year 1999
_journal_page_first 102
_journal_page_last 111
_publ_section_title
;
 Unusual M3+ cations in synthetic amphiboles with nominal fluoro-eckermannite
 composition: Deviations from stoichiometry and structural effects of the
 cummingtonite component
 Sample: V, Na.90Na.92Mg1.08Mg4.98V.02Si8O22F2
;
_chemical_formula_sum 'Si8 Mg6.12 V.02 Na1.81 O22 F2'
_cell_length_a 9.655
_cell_length_b 17.909
_cell_length_c 5.267
_cell_angle_alpha 90
_cell_angle_beta 102.73
_cell_angle_gamma 90
_cell_volume 888.338
_symmetry_space_group_name_H-M 'C 1 2/m 1'
loop_
_symmetry_equiv_pos_as_xyz
  'x,y,z'
  '1/2+x,1/2+y,z'
  'x,-y,z'
  '1/2+x,1/2-y,z'
  '-x,y,-z'
  '1/2-x,1/2+y,-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
_atom_site_occupancy
_atom_site_Uiso_or_equiv
Si(1)   0.28440   0.08480   0.28160   1.00000   0.00621
Si(2)   0.29240   0.17060   0.78610   1.00000   0.00697
Mg(1)   0.00000   0.08870   0.50000   1.00000   0.00811
V(2)   0.00000   0.17920   0.00000   0.01000   0.01001
Mg(2)   0.00000   0.17920   0.00000   0.99000   0.01001
Mg(3)   0.00000   0.00000   0.00000   1.00000   0.00773
Mg(4)   0.00000   0.26310   0.50000   0.57000   0.02115
Na(4)   0.00000   0.26310   0.50000   0.43000   0.02115
NaA   0.00000   0.50000   0.00000   0.25000   0.03584
NaA(m)   0.04410   0.50000   0.10260   0.35000   0.03217
O1   0.11390   0.08470   0.21340   1.00000   0.00671
O2   0.12070   0.16960   0.72090   1.00000   0.00912
F3   0.10410   0.00000   0.70680   1.00000   0.00925
O4   0.36890   0.24830   0.78300   1.00000   0.01836
O5   0.35020   0.12790   0.06710   1.00000   0.02128
O6   0.34740   0.11890   0.56780   1.00000   0.02850
O7   0.34560   0.00000   0.28290   1.00000   0.01267