data_global
_chemical_name_mineral 'Pigeonite'
loop_
_publ_author_name
'Nestola F'
'Tribaudino M'
'Ballaran T B'
_journal_name_full 'American Mineralogist'
_journal_volume 89 
_journal_year 2004
_journal_page_first 189
_journal_page_last 196
_publ_section_title
;
 High pressure behavior, transformation and crystal structure of synthetic iron-free pigeonite
 Sample: P = 6.2 GPa
;
_database_code_amcsd 0003200
_chemical_formula_sum 'Mg1.85 Ca.15 Si2 O6'
_cell_length_a 9.291
_cell_length_b 8.679
_cell_length_c 4.963
_cell_angle_alpha 90
_cell_angle_beta 102.22
_cell_angle_gamma 90
_cell_volume 391.132
_exptl_crystal_density_diffrn      3.450
_symmetry_space_group_name_H-M 'C 1 2/c 1'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '1/2+x,1/2+y,z'
  'x,-y,1/2+z'
  '1/2+x,1/2-y,1/2+z'
  '-x,y,1/2-z'
  '1/2-x,1/2+y,1/2-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_U_iso_or_equiv
MgM2   0.00000   0.27890   0.25000   0.85000   0.01013
CaM2   0.00000   0.27890   0.25000   0.15000   0.01013
MgM1   0.00000   0.90650   0.25000   1.00000   0.00697
SiT   0.29760   0.09180   0.21390   1.00000   0.00621
O1   0.12140   0.09050   0.13900   1.00000   0.00798
O2   0.37640   0.23910   0.36400   1.00000   0.01051
O3   0.35460   0.05620   0.92500   1.00000   0.00874
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
MgM2 0.00930 0.01470 0.00730 0.00000 0.00170 0.00000
CaM2 0.00930 0.01470 0.00730 0.00000 0.00170 0.00000