data_global
_chemical_name_mineral 'Diopside'
loop_
_publ_author_name
'Raudsepp M'
'Hawthorne F C'
'Turnock A C'
_journal_name_full 'American Mineralogist'
_journal_volume 75 
_journal_year 1990
_journal_page_first 1274
_journal_page_last 1281
_publ_section_title
;
 Crystal chemistry of synthetic pyroxenes on the join CaNiSi2O6-CaMgSi2O6
 (diopside): A Rietveld refinement study
 sample Ni25, CaNi.22Mg.78Si2O6
;
_database_code_amcsd 0001336
_chemical_formula_sum '(Ni.22 Mg.78) Ca Si2 O6'
_cell_length_a 9.7393
_cell_length_b 8.9095
_cell_length_c 5.2418
_cell_angle_alpha 90
_cell_angle_beta 105.850
_cell_angle_gamma 90
_cell_volume 437.550
_exptl_crystal_density_diffrn      3.402
_symmetry_space_group_name_H-M 'C 1 2/c 1'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '1/2+x,1/2+y,z'
  'x,-y,1/2+z'
  '1/2+x,1/2-y,1/2+z'
  '-x,y,1/2-z'
  '1/2-x,1/2+y,1/2-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
Ni1   0.00000   0.90720   0.25000   0.22000   0.00469
Mg1   0.00000   0.90720   0.25000   0.78000   0.00469
Ca2   0.00000   0.30000   0.25000   1.00000   0.00804
Si   0.28760   0.09050   0.22990   1.00000   0.00442
O1   0.11580   0.08610   0.14070   1.00000   0.00646
O2   0.36330   0.24880   0.32180   1.00000   0.00823
O3   0.34900   0.01800   0.99280   1.00000   0.00709