data_global _chemical_name_mineral 'Anhydrite' loop_ _publ_author_name 'Kirfel A' 'Will G' _journal_name_full 'Acta Crystallographica, Section B' _journal_volume 36 _journal_year 1980 _journal_page_first 2881 _journal_page_last 2890 _publ_section_title ; Charge density in anhydrite, CaSO4, from X-ray and neutron diffraction measurements ; _database_code_amcsd 0020854 _chemical_compound_source 'Stassfurt, Germany' _chemical_formula_sum 'Ca S O4' _cell_length_a 7.006 _cell_length_b 6.998 _cell_length_c 6.245 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 90 _cell_volume 306.180 _exptl_crystal_density_diffrn 2.953 _symmetry_space_group_name_H-M 'A m m a' loop_ _space_group_symop_operation_xyz 'x,y,z' 'x,1/2+y,1/2+z' '1/2+x,y,-z' '1/2+x,1/2+y,1/2-z' '1/2-x,-y,z' '1/2-x,1/2-y,1/2+z' 'x,-y,z' 'x,1/2-y,1/2+z' '-x,y,-z' '-x,1/2+y,1/2-z' '1/2-x,y,z' '1/2-x,1/2+y,1/2+z' '1/2+x,-y,-z' '1/2+x,1/2-y,1/2-z' '-x,-y,-z' '-x,1/2-y,1/2-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_U_iso_or_equiv Ca 0.75000 0.00000 0.34765 ? S 0.25000 0.00000 0.15577 ? O1 0.25000 0.16956 0.01607 ? O2 0.08202 0.00000 0.29735 ? 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 0.00680 0.00950 0.00680 0.00000 0.00000 0.00000 S 0.00590 0.00690 0.00470 0.00000 0.00000 0.00000 O1 0.01780 0.00840 0.00900 0.00000 0.00000 0.00240 O2 0.00640 0.01730 0.00910 0.00000 0.00150 0.00000