data_global _chemical_name_mineral 'Calcite' loop_ _publ_author_name 'Paquette J' 'Reeder R J' _journal_name_full 'American Mineralogist' _journal_volume 75 _journal_year 1990 _journal_page_first 1151 _journal_page_last 1158 _publ_section_title ; Single-crystal X-ray structure refinements of two biogenic magnesian calcite crystals sample LB ; _database_code_amcsd 0001328 _chemical_formula_sum '(Ca.871 Mg.129) C O3' _cell_length_a 4.9382 _cell_length_b 4.9382 _cell_length_c 16.832 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 120 _cell_volume 355.471 _exptl_crystal_density_diffrn 2.748 _symmetry_space_group_name_H-M 'R -3 2/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 0.87100 Mg 0.00000 0.00000 0.00000 0.12900 C 0.00000 0.00000 0.25000 1.00000 O 0.25870 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 0.01760 0.01760 0.01880 0.00880 0.00000 0.00000 Mg 0.01760 0.01760 0.01880 0.00880 0.00000 0.00000 C 0.01584 0.01584 0.02110 0.00792 0.00000 0.00000 O 0.02066 0.04077 0.03717 0.02038 -0.00328 -0.00656