data_global _chemical_name_mineral 'Helium' loop_ _publ_author_name 'Schuch A F' 'Grilly E R' 'Mills R L' _journal_name_full 'Physical Review' _journal_volume 110 _journal_year 1958 _journal_page_first 775 _journal_page_last 775 _publ_section_title ; Structure of the alpha and beta forms of solid He Sample: at T = 1.9 K & P = .01 GPa Note: structure known as the alpha form ; _database_code_amcsd 0015153 _chemical_compound_source 'Synthetic' _chemical_formula_sum 'He' _cell_length_a 4.01 _cell_length_b 4.01 _cell_length_c 4.01 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 90 _cell_volume 64.481 _exptl_crystal_density_diffrn 0.206 _symmetry_space_group_name_H-M 'I m 3 m' loop_ _space_group_symop_operation_xyz 'x,y,z' '1/2+x,1/2+y,1/2+z' 'z,-x,y' '1/2+z,1/2-x,1/2+y' '-y,z,-x' '1/2-y,1/2+z,1/2-x' 'x,-y,z' '1/2+x,1/2-y,1/2+z' '-z,x,-y' '1/2-z,1/2+x,1/2-y' 'y,-z,x' '1/2+y,1/2-z,1/2+x' '-x,y,-z' '1/2-x,1/2+y,1/2-z' 'x,-z,-y' '1/2+x,1/2-z,1/2-y' '-z,y,x' '1/2-z,1/2+y,1/2+x' 'y,-x,-z' '1/2+y,1/2-x,1/2-z' '-x,z,y' '1/2-x,1/2+z,1/2+y' 'z,-y,-x' '1/2+z,1/2-y,1/2-x' '-y,x,z' '1/2-y,1/2+x,1/2+z' 'x,z,y' '1/2+x,1/2+z,1/2+y' '-z,-y,-x' '1/2-z,1/2-y,1/2-x' 'y,x,z' '1/2+y,1/2+x,1/2+z' '-x,-z,-y' '1/2-x,1/2-z,1/2-y' 'z,y,x' '1/2+z,1/2+y,1/2+x' '-y,-x,-z' '1/2-y,1/2-x,1/2-z' 'z,x,-y' '1/2+z,1/2+x,1/2-y' '-y,-z,x' '1/2-y,1/2-z,1/2+x' 'x,y,-z' '1/2+x,1/2+y,1/2-z' '-z,-x,y' '1/2-z,1/2-x,1/2+y' 'y,z,-x' '1/2+y,1/2+z,1/2-x' '-x,-y,z' '1/2-x,1/2-y,1/2+z' '-z,x,y' '1/2-z,1/2+x,1/2+y' 'y,-z,-x' '1/2+y,1/2-z,1/2-x' '-x,y,z' '1/2-x,1/2+y,1/2+z' 'z,-x,-y' '1/2+z,1/2-x,1/2-y' '-y,z,x' '1/2-y,1/2+z,1/2+x' 'x,-y,-z' '1/2+x,1/2-y,1/2-z' '-x,z,-y' '1/2-x,1/2+z,1/2-y' 'z,-y,x' '1/2+z,1/2-y,1/2+x' '-y,x,-z' '1/2-y,1/2+x,1/2-z' 'x,-z,y' '1/2+x,1/2-z,1/2+y' '-z,y,-x' '1/2-z,1/2+y,1/2-x' 'y,-x,z' '1/2+y,1/2-x,1/2+z' '-x,-z,y' '1/2-x,1/2-z,1/2+y' 'z,y,-x' '1/2+z,1/2+y,1/2-x' '-y,-x,z' '1/2-y,1/2-x,1/2+z' 'x,z,-y' '1/2+x,1/2+z,1/2-y' '-z,-y,x' '1/2-z,1/2-y,1/2+x' 'y,x,-z' '1/2+y,1/2+x,1/2-z' '-z,-x,-y' '1/2-z,1/2-x,1/2-y' 'y,z,x' '1/2+y,1/2+z,1/2+x' '-x,-y,-z' '1/2-x,1/2-y,1/2-z' 'z,x,y' '1/2+z,1/2+x,1/2+y' '-y,-z,-x' '1/2-y,1/2-z,1/2-x' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z He 0.00000 0.00000 0.00000