data_global _chemical_name_mineral 'Marshite' loop_ _publ_author_name 'Hull S' 'Keen D A' _journal_name_full 'Physical Review' _journal_volume B50 _journal_year 1994 _journal_page_first 5868 _journal_page_last 5885 _publ_section_title ; High-pressure polymorphism of the copper(I) halides: A neutron-diffraction study to ~10 GPa Note: P = 1.74 GPa Note: known as CuI-IV ; _database_code_amcsd 0015181 _chemical_formula_sum 'Cu I' _cell_length_a 4.155 _cell_length_b 4.155 _cell_length_c 20.48 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 120 _cell_volume 306.198 _exptl_crystal_density_diffrn 6.197 _symmetry_space_group_name_H-M 'R -3 m' loop_ _space_group_symop_operation_xyz 'x,y,z' '2/3+x,1/3+y,1/3+z' '1/3+x,2/3+y,2/3+z' 'x,x-y,z' '2/3+x,1/3+x-y,1/3+z' '1/3+x,2/3+x-y,2/3+z' 'y,x,-z' '2/3+y,1/3+x,1/3-z' '1/3+y,2/3+x,2/3-z' '-x+y,y,z' '2/3-x+y,1/3+y,1/3+z' '1/3-x+y,2/3+y,2/3+z' '-x,-x+y,-z' '2/3-x,1/3-x+y,1/3-z' '1/3-x,2/3-x+y,2/3-z' '-y,-x,z' '2/3-y,1/3-x,1/3+z' '1/3-y,2/3-x,2/3+z' 'x-y,-y,-z' '2/3+x-y,1/3-y,1/3-z' '1/3+x-y,2/3-y,2/3-z' 'y,-x+y,-z' '2/3+y,1/3-x+y,1/3-z' '1/3+y,2/3-x+y,2/3-z' '-x+y,-x,z' '2/3-x+y,1/3-x,1/3+z' '1/3-x+y,2/3-x,2/3+z' '-x,-y,-z' '2/3-x,1/3-y,1/3-z' '1/3-x,2/3-y,2/3-z' '-y,x-y,z' '2/3-y,1/3+x-y,1/3+z' '1/3-y,2/3+x-y,2/3+z' 'x-y,x,-z' '2/3+x-y,1/3+x,1/3-z' '1/3+x-y,2/3+x,2/3-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_U_iso_or_equiv Cu 0.00000 0.00000 0.12930 0.04433 I1 0.00000 0.00000 0.00000 0.01900 I2 0.00000 0.00000 0.50000 0.01900