data_global _chemical_name_mineral 'Nuffieldite' loop_ _publ_author_name 'Kohatsu I' 'Wuensch B J' _journal_name_full 'Zeitschrift fur Kristallographie' _journal_volume 138 _journal_year 1973 _journal_page_first 343 _journal_page_last 365 _publ_section_title ; The crystal structure of nuffieldite, Pb2Cu(Pb,Bi)Bi2S7 ; _database_code_amcsd 0017790 _chemical_compound_source 'Alice Arm, British Columbia, Canada' _chemical_formula_sum 'Pb2.5 Bi2.5 Cu S7' _cell_length_a 14.387 _cell_length_b 21.011 _cell_length_c 4.046 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 90 _cell_volume 1223.046 _exptl_crystal_density_diffrn 14.429 _symmetry_space_group_name_H-M 'P b m n' 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' '-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_occupancy _atom_site_U_iso_or_equiv PbM1 0.15990 0.19290 0.25000 0.50000 0.01140 BiM1 0.15990 0.19290 0.25000 0.50000 0.01140 PbM2 0.39360 0.33470 0.25000 1.00000 0.01115 PbM3 0.63190 0.02110 0.25000 1.00000 0.02584 BiM4 0.60750 0.47240 0.25000 1.00000 0.01444 BiM5 0.95790 0.34310 0.25000 1.00000 0.01254 Cu 0.66910 0.17220 0.25000 1.00000 0.01140 S1 0.54170 0.23990 0.25000 1.00000 0.04559 S2 0.01690 0.11170 0.25000 1.00000 0.01773 S3 0.47180 0.06760 0.25000 1.00000 0.00013 S4 0.80260 0.22760 0.25000 1.00000 0.00253 S5 0.14380 0.37240 0.25000 1.00000 0.01140 S6 0.74170 0.38830 0.25000 1.00000 0.03166 S7 0.31900 0.46870 0.25000 1.00000 0.00633