data_global
_chemical_name_mineral 'Calcite'
loop_
_publ_author_name
'Althoff P L'
_journal_name_full 'American Mineralogist'
_journal_volume 62 
_journal_year 1977
_journal_page_first 772
_journal_page_last 783
_publ_section_title
;
 Structural refinements of dolomite and a magnesian calcite and implications for
 dolomite formation in the marine environment
 Mg-calcite
;
_database_code_amcsd 0000585
_chemical_formula_sum '(Ca.9 Mg.1) C O3'
_cell_length_a 4.941
_cell_length_b 4.941
_cell_length_c 16.864
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 120
_cell_volume 356.550
_exptl_crystal_density_diffrn      2.753
_symmetry_space_group_name_H-M 'R -3 c'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '2/3+x,1/3+y,1/3+z'
  '1/3+x,2/3+y,2/3+z'
  'x,x-y,1/2+z'
  '2/3+x,1/3+x-y,5/6+z'
  '1/3+x,2/3+x-y,1/6+z'
  'y,x,1/2-z'
  '2/3+y,1/3+x,5/6-z'
  '1/3+y,2/3+x,1/6-z'
  '-x+y,y,1/2+z'
  '2/3-x+y,1/3+y,5/6+z'
  '1/3-x+y,2/3+y,1/6+z'
  '-x,-x+y,1/2-z'
  '2/3-x,1/3-x+y,5/6-z'
  '1/3-x,2/3-x+y,1/6-z'
  '-y,-x,1/2+z'
  '2/3-y,1/3-x,5/6+z'
  '1/3-y,2/3-x,1/6+z'
  'x-y,-y,1/2-z'
  '2/3+x-y,1/3-y,5/6-z'
  '1/3+x-y,2/3-y,1/6-z'
  'y,-x+y,-z'
  '2/3+y,1/3-x+y,1/3-z'
  '1/3+y,2/3-x+y,2/3-z'
  '-x+y,-x,z'
  '2/3-x+y,1/3-x,1/3+z'
  '1/3-x+y,2/3-x,2/3+z'
  '-x,-y,-z'
  '2/3-x,1/3-y,1/3-z'
  '1/3-x,2/3-y,2/3-z'
  '-y,x-y,z'
  '2/3-y,1/3+x-y,1/3+z'
  '1/3-y,2/3+x-y,2/3+z'
  'x-y,x,-z'
  '2/3+x-y,1/3+x,1/3-z'
  '1/3+x-y,2/3+x,2/3-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
Ca   0.00000   0.00000   0.00000   0.90000
Mg   0.00000   0.00000   0.00000   0.10000
C   0.00000   0.00000   0.25000   1.00000
O   0.25830   0.00000   0.25000   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
Ca 0.02310 0.02310 0.02204 0.01155 0.00000 0.00000
Mg 0.00186 0.00186 0.00288 0.00093 0.00000 0.00000
C 0.01651 0.01651 0.01873 0.00826 0.00000 0.00000
O 0.02505 0.04545 0.04034 0.02273 -0.00475 -0.00950