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: hgj, T = 950 C
;
_database_code_amcsd 0008641
_chemical_compound_source 'from rhyodacite, Parana, Brazil'
_chemical_formula_sum '(Mg.468 Fe.411 Mn.014 Ca.107) Si O3'
_cell_length_a 9.849
_cell_length_b 9.018
_cell_length_c 5.323
_cell_angle_alpha 90
_cell_angle_beta 109.44
_cell_angle_gamma 90
_cell_volume 445.827
_exptl_crystal_density_diffrn      3.441
_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
MgM1   0.00000   0.90200   0.25000   0.69000   0.02400
FeM1   0.00000   0.90200   0.25000   0.28200   0.02400
MnM1   0.00000   0.90200   0.25000   0.00910   0.02400
CaM1   0.00000   0.90200   0.25000   0.01890   0.02400
MgM2   0.00000   0.26880   0.25000   0.24570   0.03700
FeM2   0.00000   0.26880   0.25000   0.54010   0.03700
MnM2   0.00000   0.26880   0.25000   0.01820   0.03700
CaM2   0.00000   0.26880   0.25000   0.19600   0.03700
Si   0.29480   0.08920   0.26170   1.00000   0.01900
O1   0.12070   0.08890   0.15220   1.00000   0.02400
O2   0.37350   0.24460   0.34970   1.00000   0.03400
O3   0.35230   0.01000   0.03820   1.00000   0.04200
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 0.02600 0.02500 0.02000 0.00000 0.00600 0.00000
FeM1 0.02600 0.02500 0.02000 0.00000 0.00600 0.00000
MnM1 0.02600 0.02500 0.02000 0.00000 0.00600 0.00000
CaM1 0.02600 0.02500 0.02000 0.00000 0.00600 0.00000
MgM2 0.03800 0.04300 0.02500 0.00000 0.00300 0.00000
FeM2 0.03800 0.04300 0.02500 0.00000 0.00300 0.00000
MnM2 0.03800 0.04300 0.02500 0.00000 0.00300 0.00000
CaM2 0.03800 0.04300 0.02500 0.00000 0.00300 0.00000
Si 0.01700 0.01900 0.01900 -0.00200 0.00600 -0.00200
O1 0.01800 0.03000 0.02400 0.00100 0.00500 -0.00100
O2 0.03900 0.02600 0.04000 -0.01300 0.01700 -0.00900
O3 0.02700 0.06100 0.03700 -0.00400 0.01000 -0.02700