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: hga, T = 25 C
;
_database_code_amcsd 0008637
_chemical_compound_source 'from rhyodacite, Parana, Brazil'
_chemical_formula_sum '(Mg.463 Fe.416 Mn.014 Ca.107) Si O3'
_cell_length_a 9.719
_cell_length_b 8.947
_cell_length_c 5.251
_cell_angle_alpha 90
_cell_angle_beta 108.49
_cell_angle_gamma 90
_cell_volume 433.035
_exptl_crystal_density_diffrn      3.547
_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   0.25060   0.65480   0.23170   0.76680   0.00600
FeM1   0.25060   0.65480   0.23170   0.20820   0.00600
MnM1   0.25060   0.65480   0.23170   0.00670   0.00600
CaM1   0.25060   0.65480   0.23170   0.01830   0.00600
MgM2   0.25520   0.01920   0.22940   0.15960   0.01100
FeM2   0.25520   0.01920   0.22940   0.62450   0.01100
MnM2   0.25520   0.01920   0.22940   0.02060   0.01100
CaM2   0.25520   0.01920   0.22940   0.19530   0.01100
SiA   0.04260   0.34050   0.27610   1.00000   0.00700
SiB   0.54930   0.83740   0.23820   1.00000   0.00600
O1A   0.86730   0.33830   0.16850   1.00000   0.00900
O1B   0.37350   0.83670   0.13420   1.00000   0.00900
O2A   0.12150   0.49940   0.33160   1.00000   0.01100
O2B   0.62860   0.98810   0.37190   1.00000   0.01400
O3A   0.10420   0.26050   0.57580   1.00000   0.01700
O3B   0.60500   0.71000   0.48060   1.00000   0.01300
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 0.00700 0.00600 0.00700 0.00000 0.00300 0.00000
FeM1 0.00700 0.00600 0.00700 0.00000 0.00300 0.00000
MnM1 0.00700 0.00600 0.00700 0.00000 0.00300 0.00000
CaM1 0.00700 0.00600 0.00700 0.00000 0.00300 0.00000
MgM2 0.00900 0.01600 0.00800 0.00100 0.00100 0.00300
FeM2 0.00900 0.01600 0.00800 0.00100 0.00100 0.00300
MnM2 0.00900 0.01600 0.00800 0.00100 0.00100 0.00300
CaM2 0.00900 0.01600 0.00800 0.00100 0.00100 0.00300
SiA 0.00600 0.00600 0.01000 -0.00100 0.00400 -0.00100
SiB 0.00600 0.00500 0.00800 -0.00100 0.00300 -0.00100
O1A 0.00700 0.00900 0.01000 0.00000 0.00200 0.00000
O1B 0.00700 0.00900 0.01100 0.00000 0.00300 0.00100
O2A 0.01200 0.00700 0.01400 -0.02600 0.00600 -0.00100
O2B 0.01400 0.01100 0.02100 -0.00600 0.01100 -0.00800
O3A 0.00700 0.02200 0.02100 0.00200 0.00400 0.01300
O3B 0.00800 0.01700 0.01400 0.00000 0.00300 0.00600