data_global
_chemical_name_mineral 'Magnocolumbite'
loop_
_publ_author_name
'Pagola S'
'Carbonio R E'
'Alonso J A'
'Fernandez-Diaz M T'
_journal_name_full 'Journal of Solid State Chemistry'
_journal_volume 134 
_journal_year 1997
_journal_page_first 76
_journal_page_last 84
_publ_section_title
;
 Crystal structure refinement of Mg Nb2 O6 columbite from neutron powder
 diffraction data and study of the ternary system MgO-Nb2O5-NbO, with evidence
 of formation of new reduced pseudobrookite Mg5-xNb4+xO15-d (1.14<x<1.60) phases
 Note: reported and calculated Biso(O2)'s do not match
;
_database_code_amcsd 0013944
_chemical_compound_source 'Synthetic'
_chemical_formula_sum 'Mg Nb2 O6'
_cell_length_a 14.1875
_cell_length_b 5.7001
_cell_length_c 5.0331
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 407.028
_exptl_crystal_density_diffrn      4.995
_symmetry_space_group_name_H-M 'P b c n'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  'x,-y,1/2+z'
  '-x,y,1/2-z'
  '1/2-x,1/2+y,z'
  '1/2+x,1/2-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
_atom_site_U_iso_or_equiv
Mg   0.00000   0.16880   0.25000   0.00507
Nb   0.15993   0.31810   0.75380   0.00304
O1   0.09550   0.39440   0.43210   0.00469
O2   0.07960   0.11630   0.90770   0.00317
O3   0.25600   0.12220   0.58330   0.00418
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
Mg 0.00387 0.00807 0.00424 0.00000 -0.00036 0.00000
Nb 0.00286 0.00230 0.00359 0.00041 0.00181 0.00160
O1 0.00683 0.00412 0.00424 -0.00041 -0.00145 0.00160
O2 0.00489 0.01037 0.00411 -0.00246 0.00036 0.00015
O3 0.00520 0.00214 0.00372 0.00246 0.00217 -0.00029