data_global
_chemical_name_mineral 'Chopinite'
loop_
_publ_author_name
'Grew E S'
'Armbruster T'
'Medenbach O'
'Yates M G'
'Carson C J'
_journal_name_full 'European Journal of Mineralogy'
_journal_volume 19 
_journal_year 2007
_journal_page_first 229
_journal_page_last 245
_publ_section_title
;
 Chopinite, [(Mg,Fe)3_](PO4)2, a new mineral isostructural with sarcopside,
 from a fluorapatite segregation in granulite-facies paragneiss, Larsemann Hills,
 Prydz Bay, East Antarctica
;
_database_code_amcsd 0007216
_chemical_compound_source 'Brattnevet, Larsemann Hills, Prydz Bay, East Antarctica'
_chemical_formula_sum '(Mg2.268 Fe.732) P2 O8'
_cell_length_a 5.9305
_cell_length_b 4.7583
_cell_length_c 10.2566
_cell_angle_alpha 90
_cell_angle_beta 90.663
_cell_angle_gamma 90
_cell_volume 289.413
_exptl_crystal_density_diffrn      3.281
_symmetry_space_group_name_H-M 'P 1 21/c 1'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  'x,1/2-y,1/2+z'
  '-x,1/2+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
Mg1   0.50000   0.00000   0.50000   0.48200   0.00975
Fe1   0.50000   0.00000   0.50000   0.51800   0.00975
Fe2   0.23770   0.01180   0.77910   0.10700   0.00887
Mg2   0.23770   0.01180   0.77910   0.89300   0.00887
P   0.25620  -0.42930   0.59884   1.00000   0.00963
O1   0.27560   0.25190   0.60580   1.00000   0.01127
O2   0.25520  -0.31890   0.45880   1.00000   0.01165
O3   0.06120  -0.31530   0.67890   1.00000   0.01229
O4   0.53340   0.27810   0.33730   1.00000   0.01203
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
Mg1 0.01260 0.00650 0.01030 -0.00060 0.00240 0.00010
Fe1 0.01260 0.00650 0.01030 -0.00060 0.00240 0.00010
Fe2 0.00930 0.00880 0.00860 -0.00010 0.00090 0.00010
Mg2 0.00930 0.00880 0.00860 -0.00010 0.00090 0.00010
P 0.01120 0.00780 0.00990 0.00000 0.00050 -0.00020
O1 0.01300 0.00900 0.01200 0.00090 0.00140 -0.00070
O2 0.01400 0.01150 0.01010 -0.00100 -0.00030 -0.00020
O3 0.01100 0.01100 0.01500 -0.00080 0.00330 -0.00190
O4 0.01300 0.00960 0.01400 0.00000 0.00030 -0.00140