data_global
_chemical_name_mineral 'Pigeonite'
loop_
_publ_author_name
'Camara F'
'Carpenter M A'
'Domeneghetti M C'
'Tazzoli V'
_journal_name_full 'American Mineralogist'
_journal_volume 88 
_journal_year 2003
_journal_page_first 1115
_journal_page_last 1128
_publ_section_title
;
 Coupling between non-convergent ordering and transition temperature
 in the C2/c - P2_1/c phase transition in pigeonite
 Sample: BTS-308 n.17-3, after heating at 750 deg C
;
_database_code_amcsd 0003149
_chemical_compound_source 'Parana, Brazil'
_chemical_formula_sum 'O6 Si2 Mg.921 Fe.835 Mn.027 Ca.195'
_cell_length_a 9.707
_cell_length_b 8.941
_cell_length_c 5.247
_cell_angle_alpha 90
_cell_angle_beta 108.48
_cell_angle_gamma 90
_cell_volume 431.906
_exptl_crystal_density_diffrn      3.545
_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
_atom_site_U_iso_or_equiv
O1A  -0.13260   0.33850   0.16990   1.00000   0.00800
O1b   0.37380   0.83690   0.13430   1.00000   0.00900
O2A   0.12170   0.49960   0.33160   1.00000   0.01100
O2B   0.62930   0.98740   0.37370   1.00000   0.01400
O3A   0.10450   0.23720   0.07990   1.00000   0.01700
O3B   0.60500   0.70860   0.47910   1.00000   0.01400
SiA   0.04270   0.34040   0.27760   1.00000   0.00700
SiB   0.54960   0.83740   0.23820   1.00000   0.00700
MgM1   0.25040   0.65460   0.23100   0.71590   0.00700
FeM1   0.25040   0.65460   0.23100   0.25440   0.00700
MnM1   0.25040   0.65460   0.23100   0.00820   0.00700
CaM2   0.25540   0.01880   0.22860   0.19530   0.01100
MgM2   0.25540   0.01880   0.22860   0.20490   0.01100
FeM2   0.25540   0.01880   0.22860   0.58070   0.01100
MnM2   0.25540   0.01880   0.22860   0.01910   0.01100
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
O1A 0.00600 0.01000 0.00900 0.00000 0.00200 0.00000
O1b 0.00600 0.01000 0.01000 0.00000 0.00200 0.00000
O2A 0.01200 0.00700 0.01300 -0.00300 0.00500 -0.00100
O2B 0.01400 0.01100 0.02000 -0.00600 0.01000 -0.00700
O3A 0.00900 0.02200 0.01800 -0.00100 0.00400 0.00000
O3B 0.00800 0.02000 0.01300 0.00100 0.00300 0.00800
SiA 0.00600 0.00600 0.01000 -0.00100 0.00300 -0.00100
SiB 0.00600 0.00600 0.00800 -0.00100 0.00300 -0.00100
MgM1 0.00700 0.00600 0.00800 0.00900 0.00000 0.00200
FeM1 0.00700 0.00600 0.00800 0.00900 0.00000 0.00200
MnM1 0.00700 0.00600 0.00800 0.00900 0.00000 0.00200
CaM2 0.00900 0.01600 0.00800 0.00200 0.00100 0.00200
MgM2 0.00900 0.01600 0.00800 0.00200 0.00100 0.00200
FeM2 0.00900 0.01600 0.00800 0.00200 0.00100 0.00200
MnM2 0.00900 0.01600 0.00800 0.00200 0.00100 0.00200