data_5000219 _chemical_name_systematic 'Arsenic' _chemical_name_mineral 'Arsenic' _chemical_formula_structural 'As' _chemical_formula_sum 'As' _publ_section_title ; The Crystal Structure of Arsenic at 4.2, 78 and 299K ; loop_ _publ_author_name 'Schiferl, D' 'Barrett, C S' _journal_name_full 'Journal of Applied Crystallography' _journal_volume 2 _journal_year 1969 _journal_page_first 30 _journal_page_last 36 _cell_length_a 3.7597(1) _cell_length_b 3.7597(1) _cell_length_c 10.4412(2) _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 120 _cell_volume 127.8 _cell_formula_units_Z 6 _symmetry_space_group_name_H-M 'R -3 m H' _symmetry_Int_Tables_number 166 _symmetry_cell_setting trigonal loop_ _symmetry_equiv_pos_as_xyz 'x,y,z' '-y,x-y,z' 'y-x,-x,z' '-y,-x,z' 'x,x-y,z' 'y-x,y,z' '-x,-y,-z' 'y,y-x,-z' 'x-y,x,-z' 'y,x,-z' '-x,y-x,-z' 'x-y,-y,-z' '1/3+x,2/3+y,2/3+z' '2/3+x,1/3+y,1/3+z' '1/3-y,2/3+x-y,2/3+z' '2/3-y,1/3+x-y,1/3+z' '1/3-x+y,2/3-x,2/3+z' '2/3-x+y,1/3-x,1/3+z' '1/3-y,2/3-x,2/3+z' '2/3-y,1/3-x,1/3+z' '1/3+x,2/3+x-y,2/3+z' '2/3+x,1/3+x-y,1/3+z' '1/3-x+y,2/3+y,2/3+z' '2/3-x+y,1/3+y,1/3+z' '1/3-x,2/3-y,2/3-z' '2/3-x,1/3-y,1/3-z' '1/3+y,2/3-x+y,2/3-z' '2/3+y,1/3-x+y,1/3-z' '1/3+x-y,2/3+x,2/3-z' '2/3+x-y,1/3+x,1/3-z' '1/3+y,2/3+x,2/3-z' '2/3+y,1/3+x,1/3-z' '1/3-x,2/3-x+y,2/3-z' '2/3-x,1/3-x+y,1/3-z' '1/3+x-y,2/3-y,2/3-z' '2/3+x-y,1/3-y,1/3-z' loop_ _atom_type_symbol _atom_type_oxidation_number As0 0.000 loop_ _atom_site_label _atom_site_type_symbol _atom_site_symmetry_multiplicity _atom_site_Wyckoff_symbol _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_occupancy _atom_site_attached_hydrogens _atom_site_calc_flag As1 As0 6 c 0. 0. 0.22764(2) 1. 0 d _refine_ls_R_factor_all 0.039