data_global
_chemical_name_mineral 'Cummingtonite'
loop_
_publ_author_name
'Yang H'
'Hazen R M'
'Prewitt C T'
'Finger L W'
'Lu R'
'Hemley R J'
_journal_name_full 'American Mineralogist'
_journal_volume 83 
_journal_year 1998
_journal_page_first 288
_journal_page_last 299
_publ_section_title
;
 High-pressure single-crystal X-ray diffraction and infrared spectroscopic
 studies of the C2/m-P2_1/m phase transition in cummingtonite
 Sample: P = 0.00 GPa, in air
;
_database_code_amcsd 0001970
_chemical_formula_sum 'Fe3.471 Mg3.445 Al.008 Ca.076 Si8 O24'
_cell_length_a 9.5220
_cell_length_b 18.1833
_cell_length_c 5.3184
_cell_angle_alpha 90
_cell_angle_beta 102.020
_cell_angle_gamma 90
_cell_volume 900.646
_exptl_crystal_density_diffrn      3.280
_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
_atom_site_U_iso_or_equiv
Fe1   0.00000   0.08740   0.50000   0.40500   0.00950
Mg1   0.00000   0.08740   0.50000   0.59500   0.00950
Fe2   0.00000   0.17760   0.00000   0.20700   0.00988
Mg2   0.00000   0.17760   0.00000   0.78900   0.00988
Al2   0.00000   0.17760   0.00000   0.00400   0.00988
Fe3   0.00000   0.00000   0.00000   0.39300   0.00773
Mg3   0.00000   0.00000   0.00000   0.60700   0.00773
Fe4   0.00000   0.25920   0.50000   0.92700   0.01178
Mg4   0.00000   0.25920   0.50000   0.03500   0.01178
Ca4   0.00000   0.25920   0.50000   0.03800   0.01178
Si1   0.28650   0.08410   0.27350   1.00000   0.00849
Si2   0.29720   0.16850   0.78000   1.00000   0.00760
O1   0.11390   0.08750   0.20700   1.00000   0.00963
O2   0.12430   0.17290   0.71810   1.00000   0.01140
O3   0.11810   0.00000   0.70810   1.00000   0.01102
O4   0.38080   0.24500   0.76820   1.00000   0.01203
O5   0.35180   0.13020   0.06220   1.00000   0.01089
O6   0.35040   0.11900   0.55580   1.00000   0.01482
O7   0.34330   0.00000   0.27230   1.00000   0.01191