data_global
_chemical_name_mineral 'Pigeonite'
loop_
_publ_author_name
'Morimoto N'
'Guven N'
_journal_name_full 'American Mineralogist'
_journal_volume 55
_journal_year 1970
_journal_page_first 1195
_journal_page_last 1209
_publ_section_title
;
 Refinement of the crystal structure of pigeonite
;
_database_code_amcsd 209
_chemical_compound_source 'Isle of Mull, Scotland'
_chemical_formula_sum 'Mg.78 Fe1.04 Ca.18 Si2 O6'
_cell_length_a 9.706
_cell_length_b 8.95
_cell_length_c 5.246
_cell_angle_alpha 90.0
_cell_angle_beta 108.59
_cell_angle_gamma 90.0
_cell_volume 431.936
_exptl_crystal_density_diffrn  3.636
_symmetry_space_group_name_H-M 'P 1 21/c 1'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  'x,1/2-y,1/2+z'
  '-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_occupancy
Mg1   0.2508  0.6548  0.2328  0.72
Fe1   0.2508  0.6548  0.2328  0.28
Fe2   0.2564  0.0183  0.2308  0.76
Ca2   0.2564  0.0183  0.2308  0.18
Mg2   0.2564  0.0183  0.2308  0.06
SiA   0.0427  0.3398  0.2797  1.0
SiB   0.5504  0.8367  0.2372  1.0
O1A   0.8659  0.3404  0.1715  1.0
O2A   0.122  0.497  0.3306  1.0
O3A   0.1037  0.2633  0.5779  1.0
O1B   0.3743  0.8342  0.1344  1.0
O2B   0.629  0.9877  0.3765  1.0
O3B   0.6053  0.7087  0.4773  1.0
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
Mg1   0.00729  0.00649  0.00977  0.00042  0.00301  0.00023
Fe1   0.00729  0.00649  0.00977  0.00042  0.00301  0.00023
Fe2   0.01201  0.01826  0.01428  0.00209  0.00162  0.00113
Ca2   0.01201  0.01826  0.01428  0.00209  0.00162  0.00113
Mg2   0.01201  0.01826  0.01428  0.00209  0.00162  0.00113
SiA   0.00729  0.00609  0.00864  -0.00042  0.00232  -0.00271
SiB   0.006  0.00649  0.00651  -0.00167  0.00185  0.00135
O1A   0.00472  0.00933  0.00839  -0.00167  0.0007  -0.00293
O2A   0.01758  0.00528  0.00952  -0.00083  0.00742  -0.0018
O3A   0.006  0.01217  0.01516  -0.0025  0.00185  0.00519
O1B   0.00986  0.00649  0.00701  0.00125  0.00394  -0.00158
O2B   0.00943  0.01826  0.01741  -0.00751  0.00765  -0.00744
O3B   0.00429  0.01542  0.01328  -0.00209  0.0007  0.00541