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 = 0.60 GPa
;
_database_code_amcsd 0001971
_chemical_formula_sum 'Fe3.471 Mg3.445 Al.008 Ca.076 Si8 O24'
_cell_length_a 9.4890
_cell_length_b 18.1508
_cell_length_c 5.3102
_cell_angle_alpha 90
_cell_angle_beta 102.210
_cell_angle_gamma 90
_cell_volume 893.903
_exptl_crystal_density_diffrn      3.305
_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   0.08710   0.50000   0.40500   0.00874
Mg1   0.00000   0.08710   0.50000   0.59500   0.00874
Fe2   0.00000   0.17760   0.00000   0.20700   0.00899
Mg2   0.00000   0.17760   0.00000   0.78900   0.00899
Al2   0.00000   0.17760   0.00000   0.00400   0.00899
Fe3   0.00000   0.00000   0.00000   0.39300   0.00887
Mg3   0.00000   0.00000   0.00000   0.60700   0.00887
Fe4   0.00000   0.25900   0.50000   0.92700   0.01165
Mg4   0.00000   0.25900   0.50000   0.03500   0.01165
Ca4   0.00000   0.25900   0.50000   0.03800   0.01165
Si1   0.28830   0.08400   0.27570   1.00000   0.00760
Si2   0.29780   0.16860   0.78180   1.00000   0.00798
O1   0.11600   0.08710   0.20960   1.00000   0.01001
O2   0.12660   0.17240   0.72020   1.00000   0.00874
O3   0.11660   0.00000   0.70930   1.00000   0.01013
O4   0.38070   0.24510   0.76750   1.00000   0.01355
O5   0.35270   0.13090   0.06400   1.00000   0.01077
O6   0.35240   0.11840   0.56070   1.00000   0.01570
O7   0.34320   0.00000   0.26940   1.00000   0.01292