data_global
_chemical_name_mineral 'Merrillite'
loop_
_publ_author_name
'Dowty E'
_journal_name_full 'Earth and Planetary Science Letters'
_journal_volume 35 
_journal_year 1977
_journal_page_first 347
_journal_page_last 351
_publ_section_title
;
 Phosphate in Angra Dos Reis: Structure and composition of the Ca3(PO4)2 minerals
;
_database_code_amcsd 0018313
_chemical_compound_source 'Angra Dos Reis meteorite'
_chemical_formula_sum '(Mg.78 Fe.22) Ca9.45 P7 O28'
_cell_length_a 10.362
_cell_length_b 10.362
_cell_length_c 37.106
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 120
_cell_volume 3450.341
_exptl_crystal_density_diffrn      3.104
_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'
  '-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
_atom_site_U_iso_or_equiv
Mg   0.00000   0.00000   0.00000   0.78000   0.00621
Fe   0.00000   0.00000   0.00000   0.22000   0.00621
Ca(IB)   0.27000   0.12410   0.17530   1.00000   0.01520
Ca(IIA)   0.00000   0.00000   0.31410   0.45000   0.01900
Ca(IIB1)   0.27250   0.13080   0.06810   1.00000   0.00760
Ca(IIB2)   0.12610   0.28300   0.43590   1.00000   0.00823
P(A)   0.00000   0.00000   0.23480   1.00000   0.00975
P(B1)   0.31250   0.17440   0.36580   1.00000   0.00836
P(B2)   0.18210   0.32220   0.13580   1.00000   0.00671
O(IA)   0.00000   0.00000   0.19350   1.00000   0.02153
O(IB1)   0.26120   0.17880   0.32680   1.00000   0.02204
O(IB2)   0.15170   0.28860   0.17640   1.00000   0.01406
O(IIA)   0.14220   0.13810   0.24840   1.00000   0.02166
O(IIB1)   0.24170   0.01450   0.37980   1.00000   0.01925
O(IIB2)   0.28870   0.26860   0.12370   1.00000   0.01267
O(IIB3)   0.27640   0.27720   0.38850   1.00000   0.01203
O(IIB4)   0.03220   0.24530   0.11610   1.00000   0.01634
O(IIB5)   0.09200   0.17980   0.03530   1.00000   0.01406
O(IIB6)   0.17610   0.09940   0.46220   1.00000   0.00975