data_global
_chemical_name_mineral 'Pigeonite'
loop_
_publ_author_name
'Camara F'
'Carpenter M A'
'Domeneghetti M C'
'Tazzoli V'
_journal_name_full 'Physics and Chemistry of Minerals'
_journal_volume 29 
_journal_year 2002
_journal_page_first 331
_journal_page_last 340
_publ_section_title
;
 Non-convergent ordering and displacive phase transition in pigeonite:
 in situ HT XRD study
 Sample: hgg, T = 750 C
;
_database_code_amcsd 0008639
_chemical_compound_source 'from rhyodacite, Parana, Brazil'
_chemical_formula_sum '(Mg.464 Fe.416 Mn.014 Ca.107) Si O3'
_cell_length_a 9.824
_cell_length_b 9.017
_cell_length_c 5.309
_cell_angle_alpha 90
_cell_angle_beta 109.19
_cell_angle_gamma 90
_cell_volume 444.155
_exptl_crystal_density_diffrn      3.458
_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
MgM1   0.25020   0.65300   0.24290   0.72670   0.02000
FeM1   0.25020   0.65300   0.24290   0.24740   0.02000
MnM1   0.25020   0.65300   0.24290   0.00800   0.02000
CaM1   0.25020   0.65300   0.24290   0.01790   0.02000
MgM2   0.25200   0.01870   0.24140   0.20080   0.03300
FeM2   0.25200   0.01870   0.24140   0.58450   0.03300
MnM2   0.25200   0.01870   0.24140   0.01940   0.03300
CaM2   0.25200   0.01870   0.24140   0.19530   0.03300
SiA   0.04390   0.33960   0.26810   1.00000   0.01700
SiB   0.54610   0.83850   0.25250   1.00000   0.01600
O1A   0.86960   0.33800   0.15870   1.00000   0.02100
O1B   0.37240   0.83930   0.14530   1.00000   0.02200
O2A   0.12230   0.49600   0.34260   1.00000   0.02900
O2B   0.62560   0.99130   0.35970   1.00000   0.03200
O3A   0.10190   0.24840   0.55190   1.00000   0.03800
O3B   0.60340   0.72730   0.51620   1.00000   0.03600
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
MgM1 0.02100 0.02200 0.01800 0.00000 0.00500 0.00000
FeM1 0.02100 0.02200 0.01800 0.00000 0.00500 0.00000
MnM1 0.02100 0.02200 0.01800 0.00000 0.00500 0.00000
CaM1 0.02100 0.02200 0.01800 0.00000 0.00500 0.00000
MgM2 0.03300 0.03800 0.02200 0.00500 0.00200 0.00100
FeM2 0.03300 0.03800 0.02200 0.00500 0.00200 0.00100
MnM2 0.03300 0.03800 0.02200 0.00500 0.00200 0.00100
CaM2 0.03300 0.03800 0.02200 0.00500 0.00200 0.00100
SiA 0.01600 0.01800 0.01700 -0.00200 0.00600 -0.00200
SiB 0.01400 0.01600 0.01800 -0.00200 0.00500 -0.00100
O1A 0.01200 0.02700 0.02100 0.00100 0.00300 -0.00200
O1B 0.01900 0.02400 0.02300 0.00100 0.00600 0.00100
O2A 0.03600 0.01900 0.03500 -0.00800 0.01600 -0.00300
O2B 0.03100 0.03000 0.03600 -0.01200 0.01400 -0.01200
O3A 0.02100 0.05800 0.03400 0.00600 0.00800 0.02600
O3B 0.02200 0.05100 0.03600 0.00300 0.01000 0.02200