data_global _chemical_name_mineral 'Lammerite' loop_ _publ_author_name 'Hawthorne F C' _journal_name_full 'American Mineralogist' _journal_volume 71 _journal_year 1986 _journal_page_first 206 _journal_page_last 209 _publ_section_title ; Lammerite, Cu3(AsO4)2, a modulated close-packed structure ; _database_code_amcsd 0001009 _chemical_formula_sum 'Cu3 As2 O8' _cell_length_a 5.079 _cell_length_b 11.611 _cell_length_c 5.394 _cell_angle_alpha 90 _cell_angle_beta 111.72 _cell_angle_gamma 90 _cell_volume 295.513 _exptl_crystal_density_diffrn 5.265 _symmetry_space_group_name_H-M 'P 1 21/a 1' loop_ _space_group_symop_operation_xyz 'x,y,z' '1/2+x,1/2-y,z' '1/2-x,1/2+y,-z' '-x,-y,-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_U_iso_or_equiv Cu1 0.00000 0.50000 0.50000 0.01250 Cu2 0.24620 0.83670 0.85630 0.01480 As -0.11110 0.88510 0.26250 0.00960 O1 0.19210 0.91730 0.22030 0.01300 O2 -0.09460 0.81570 0.53900 0.01500 O3 0.17170 0.68710 0.99040 0.01300 O4 0.28930 0.99020 0.73320 0.01200