data_global
_chemical_name_mineral 'Cummingtonite'
loop_
_publ_author_name
'Yang H'
'Smyth J R'
_journal_name_full 'American Mineralogist'
_journal_volume 81 
_journal_year 1996
_journal_page_first 363
_journal_page_last 368
_publ_section_title
;
 Crystal structure of a P2_1/m ferromagnesian cummingtonite at 140 K
 T = 295 K
;
_database_code_amcsd 0001789
_chemical_formula_sum '(Mg4.441 Fe2.559) Si8 O24'
_cell_length_a 9.502
_cell_length_b 18.126
_cell_length_c 5.309
_cell_angle_alpha 90
_cell_angle_beta 102.07
_cell_angle_gamma 90
_cell_volume 894.172
_exptl_crystal_density_diffrn      3.192
_symmetry_space_group_name_H-M 'C 1 2/m 1'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '1/2+x,1/2+y,z'
  'x,-y,z'
  '1/2+x,1/2-y,z'
  '-x,y,-z'
  '1/2-x,1/2+y,-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
Mg1   0.00000   0.08690   0.50000   0.80000
Fe1   0.00000   0.08690   0.50000   0.20000
Mg2   0.00000   0.17720   0.00000   0.91100
Fe2   0.00000   0.17720   0.00000   0.08900
Mg3   0.00000   0.00000   0.00000   0.83100
Fe3   0.00000   0.00000   0.00000   0.16900
Mg4   0.00000   0.25910   0.50000   0.09400
Fe4   0.00000   0.25910   0.50000   0.90600
Si1   0.28770   0.08410   0.27440   1.00000
Si2   0.29770   0.16890   0.78110   1.00000
O1   0.11380   0.08710   0.20940   1.00000
O2   0.12400   0.17240   0.71940   1.00000
O3   0.11430   0.00000   0.70880   1.00000
O4   0.38030   0.24530   0.76960   1.00000
O5   0.35170   0.13120   0.06450   1.00000
O6   0.35000   0.11840   0.55880   1.00000
O7   0.34330   0.00000   0.27100   1.00000
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
Mg1 0.00919 0.00666 0.00492 0.00000 0.00196 0.00000
Fe1 0.00919 0.00666 0.00492 0.00000 0.00196 0.00000
Mg2 0.00744 0.00666 0.00655 0.00000 0.00098 0.00000
Fe2 0.00744 0.00666 0.00655 0.00000 0.00098 0.00000
Mg3 0.00875 0.00666 0.00628 0.00000 0.00024 0.00000
Fe3 0.00875 0.00666 0.00628 0.00000 0.00024 0.00000
Mg4 0.01050 0.01165 0.00765 0.00000 0.00342 0.00000
Fe4 0.01050 0.01165 0.00765 0.00000 0.00342 0.00000
Si1 0.00612 0.00499 0.00492 -0.00085 0.00049 -0.00048
Si2 0.00525 0.00499 0.00464 -0.00085 0.00024 0.00000
O1 0.00569 0.00832 0.00614 0.00000 0.00098 -0.00048
O2 0.00700 0.00832 0.00778 0.00000 0.00073 0.00191
O3 0.00962 0.00666 0.00997 0.00000 0.00220 0.00000
O4 0.01312 0.00999 0.01038 -0.00341 0.00122 0.00095
O5 0.00831 0.01498 0.00888 -0.00085 0.00122 0.00667
O6 0.00962 0.02164 0.01051 0.00256 -0.00024 -0.00572
O7 0.01181 0.00333 0.01707 0.00000 0.00244 0.00000