data_global _chemical_name_mineral 'Eucairite' loop_ _publ_author_name 'Frueh A J' 'Czamanske G K' 'Knight C' _journal_name_full 'Zeitschrift fur Kristallographie' _journal_volume 108 _journal_year 1957 _journal_page_first 389 _journal_page_last 396 _publ_section_title ; The crystallography of eucairite, CuAgSe Sample: tetragonal subcell ; _database_code_amcsd 0010579 _chemical_compound_source 'Skrikerum, Sweden' _chemical_formula_sum 'Cu Ag Se' _cell_length_a 4.083 _cell_length_b 4.083 _cell_length_c 6.31 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 90 _cell_volume 105.193 _exptl_crystal_density_diffrn 7.905 _symmetry_space_group_name_H-M 'P 4/n m m' loop_ _space_group_symop_operation_xyz 'x,y,z' '1/2-y,1/2-x,z' '1/2+y,1/2+x,-z' '1/2+y,-x,-z' '1/2-y,x,z' 'x,1/2-y,z' '-x,1/2+y,-z' '1/2+x,1/2+y,-z' '1/2-x,1/2-y,z' 'y,x,z' '-y,-x,-z' '-y,1/2+x,-z' 'y,1/2-x,z' '1/2-x,y,z' '1/2+x,-y,-z' '-x,-y,-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_occupancy Cu 0.25000 0.75000 0.10500 0.50000 Ag 0.25000 0.25000 0.44900 1.00000 Se 0.25000 0.25000 0.87300 1.00000