data_global _chemical_name_mineral 'Umangite' loop_ _publ_author_name 'Milman V' _journal_name_full 'Acta Crystallographica, Section B' _journal_volume 58 _journal_year 2002 _journal_page_first 437 _journal_page_last 447 _publ_section_title ; Klockmannite, CuSe: structure, properties and phase stability from ab initio modeling ; _database_code_amcsd 0009926 _chemical_compound_source 'hypothetical structure calculated using DFT' _chemical_formula_sum 'Cu3 Se2' _cell_length_a 6.308 _cell_length_b 6.308 _cell_length_c 4.350 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 90 _cell_volume 173.090 _exptl_crystal_density_diffrn 6.688 _symmetry_space_group_name_H-M 'P -4 21 m' loop_ _space_group_symop_operation_xyz 'x,y,z' '1/2-y,1/2-x,z' 'y,-x,-z' '1/2-x,1/2+y,-z' '-x,-y,z' '1/2+y,1/2+x,z' '-y,x,-z' '1/2+x,1/2-y,-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z Cu1 0.00000 0.00000 0.00000 Cu2 0.64300 0.85700 0.24750 Se 0.26550 0.76550 0.25860