data_global
_chemical_name_mineral 'Ilvaite'
loop_
_publ_author_name
'Ghose S'
'Tsukimura K'
'Hatch D M'
_journal_name_full 'Physics and Chemistry of Minerals'
_journal_volume 16 
_journal_year 1989
_journal_page_first 483
_journal_page_last 496
_publ_section_title
;
 Phase transitions in ilvaite, a mixed-valence iron silicate
 II. A single-crystal X-ray diffraction study and Landau theory of the
 monoclinic to orthorhombic phase transition induced by charge delocalization
 Sample: T = 340 K
;
_database_code_amcsd 0007455
_chemical_formula_sum 'Fe3 Ca Si2 O9 H'
_cell_length_a 13.0466
_cell_length_b 8.8268
_cell_length_c 5.8647
_cell_angle_alpha 90
_cell_angle_beta 90.124
_cell_angle_gamma 90
_cell_volume 675.376
_exptl_crystal_density_diffrn      4.020
_symmetry_space_group_name_H-M 'P 1 21/a 1'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '1/2+x,1/2-y,z'
  '1/2-x,1/2+y,-z'
  '-x,-y,-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_U_iso_or_equiv
FeAo   0.89022   0.05037   0.00712   0.00840
FeAm   0.89011   0.05127   0.49289   0.00810
FeB   0.94053   0.73975   0.24935   0.00890
Ca   0.81296   0.37036   0.75122   0.00910
Si1   0.95950   0.36829   0.24980   0.00600
Si2   0.67950   0.22704   0.25058   0.00630
O1   0.01030   0.02886   0.74514   0.01180
O2o   0.93663   0.27240   0.01596   0.00850
O2m   0.93591   0.27184   0.48365   0.00860
O3   0.77721   0.10951   0.25205   0.00860
O4o   0.67103   0.32924   0.01881   0.00910
O4m   0.67094   0.33020   0.48194   0.00930
O5   0.58484   0.10095   0.25066   0.00890
O6   0.60165   0.02469   0.75094   0.01160
O-H7   0.79813   0.10918   0.74803   0.00870
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
FeAo 0.00820 0.00830 0.00880 -0.00010 -0.00050 0.00060
FeAm 0.00800 0.00790 0.00850 -0.00020 0.00050 -0.00080
FeB 0.00970 0.00810 0.00910 -0.00060 -0.00010 -0.00020
Ca 0.00860 0.00770 0.01130 0.00080 -0.00010 -0.00010
Si1 0.00650 0.00610 0.00550 0.00010 -0.00020 -0.00020
Si2 0.00650 0.00650 0.00590 0.00050 -0.00030 0.00000
O1 0.01010 0.01060 0.01490 0.00250 -0.00060 0.00140
O2o 0.00970 0.00970 0.00620 -0.00140 0.00010 -0.00120
O2m 0.01100 0.00970 0.00530 -0.00120 -0.00020 0.00150
O3 0.00790 0.00810 0.01010 0.00100 0.00030 0.00010
O4o 0.01050 0.00920 0.00770 0.00020 0.00040 0.00060
O4m 0.01120 0.00940 0.00760 0.00070 -0.00050 -0.00200
O5 0.00790 0.00890 0.00990 0.00110 -0.00030 0.00010
O6 0.01030 0.00930 0.01540 -0.00240 0.00050 0.00070
O-H7 0.00910 0.00880 0.00850 0.00060 -0.00030 -0.00080