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