data_global
_chemical_name_mineral 'Enstatite'
loop_
_publ_author_name
'Hugh-Jones D A'
'Chopelas A'
'Angel R J'
_journal_name_full 'Physics and Chemistry of Minerals'
_journal_volume 24 
_journal_year 1997
_journal_page_first 301
_journal_page_last 310
_publ_section_title
;
 Tetrahedral compression in (Mg,Fe)SiO3 orthopyroxenes
 Sample: P = 4.93 GPa, natural orthopyroxene
;
_database_code_amcsd 0008023
_chemical_formula_sum 'Mg1.66 Fe.24 Ca.012 Al.14 Si1.94 O6'
_cell_length_a 18.051
_cell_length_b 8.6683
_cell_length_c 5.1244
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 801.823
_exptl_crystal_density_diffrn      3.454
_symmetry_space_group_name_H-M 'P b c a'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  'x,1/2-y,1/2+z'
  '-x,1/2+y,1/2-z'
  '1/2-x,1/2+y,z'
  '1/2+x,1/2-y,-z'
  '1/2+x,y,1/2-z'
  '1/2-x,-y,1/2+z'
  '-x,-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   0.37800   0.65580   0.85800   1.00000   0.00013
MgM2   0.37620   0.48150   0.35220   0.66000   0.00038
FeM2   0.37620   0.48150   0.35220   0.24000   0.00038
CaM2   0.37620   0.48150   0.35220   0.01200   0.00038
AlM2   0.37620   0.48150   0.35220   0.08000   0.00038
SiTA   0.27000   0.34410   0.04000   0.97000   0.00139
AlTA   0.27000   0.34410   0.04000   0.03000   0.00139
SiTB   0.47200   0.33890   0.80330   0.97000   0.00139
AlTB   0.47200   0.33890   0.80330   0.03000   0.00139
O1a   0.17900   0.33900   0.02100   1.00000   0.00342
O2a   0.30400   0.50900   0.04000   1.00000   0.00342
O3a   0.30200   0.22800   0.81900   1.00000   0.00342
O1b   0.56200   0.33700   0.81100   1.00000   0.00342
O2b   0.43000   0.48700   0.69000   1.00000   0.00342
O3b   0.44800   0.19100   0.61300   1.00000   0.00342