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: hgd, T = 650 C
;
_database_code_amcsd 0008638
_chemical_compound_source 'from rhyodacite, Parana, Brazil'
_chemical_formula_sum 'Mg.461 Fe.419 Mn.014 Ca.106 Si O3'
_cell_length_a 9.801
_cell_length_b 9.008
_cell_length_c 5.296
_cell_angle_alpha 90
_cell_angle_beta 109.01
_cell_angle_gamma 90
_cell_volume 442.070
_exptl_crystal_density_diffrn      3.477
_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   0.65320   0.23970   0.75290   0.01800
FeM1   0.25020   0.65320   0.23970   0.22220   0.01800
MnM1   0.25020   0.65320   0.23970   0.00720   0.01800
CaM1   0.25020   0.65320   0.23970   0.01790   0.01800
MgM2   0.25280   0.01880   0.23820   0.16990   0.02900
FeM2   0.25280   0.01880   0.23820   0.61480   0.02900
MnM2   0.25280   0.01880   0.23820   0.02020   0.02900
CaM2   0.25280   0.01880   0.23820   0.19510   0.02900
SiA   0.04350   0.33980   0.27030   1.00000   0.01500
SiB   0.54700   0.83810   0.24800   1.00000   0.01400
O1A   0.86910   0.33810   0.16090   1.00000   0.01900
O1B   0.37250   0.83840   0.14180   1.00000   0.02000
O2A   0.12220   0.49680   0.33970   1.00000   0.02500
O2B   0.62620   0.99050   0.36320   1.00000   0.02900
O3A   0.10240   0.25160   0.55830   1.00000   0.03500
O3B   0.60310   0.72220   0.50450   1.00000   0.03100
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 0.01900 0.01900 0.01600 0.00000 0.00300 0.00000
FeM1 0.01900 0.01900 0.01600 0.00000 0.00300 0.00000
MnM1 0.01900 0.01900 0.01600 0.00000 0.00300 0.00000
CaM1 0.01900 0.01900 0.01600 0.00000 0.00300 0.00000
MgM2 0.02900 0.03400 0.02000 0.00300 0.00200 0.00200
FeM2 0.02900 0.03400 0.02000 0.00300 0.00200 0.00200
MnM2 0.02900 0.03400 0.02000 0.00300 0.00200 0.00200
CaM2 0.02900 0.03400 0.02000 0.00300 0.00200 0.00200
SiA 0.01400 0.01600 0.01600 -0.00100 0.00600 -0.00200
SiB 0.01300 0.01500 0.01600 -0.00200 0.00500 -0.00100
O1A 0.01400 0.02400 0.01900 0.00100 0.00500 0.00100
O1B 0.01400 0.02300 0.02100 0.00100 0.00400 -0.00100
O2A 0.03000 0.01700 0.03200 -0.00800 0.01400 -0.00300
O2B 0.03000 0.02600 0.03200 -0.01100 0.01400 -0.01000
O3A 0.01800 0.05200 0.03200 0.00300 0.00600 0.02300
O3B 0.02100 0.04300 0.02900 0.00400 0.00900 0.01900