data_global _chemical_name_mineral 'Orthoclase' loop_ _publ_author_name 'Fenn P M' 'Brown G E' _journal_name_full 'Zeitschrift fur Kristallographie' _journal_volume 145 _journal_year 1977 _journal_page_first 124 _journal_page_last 145 _publ_section_title ; Crystal structure of a synthetic, compositionally intermediate, hypersolvus alkali feldspar: evidence for Na, K site ordering ; _database_code_amcsd 0020553 _chemical_compound_source 'Synthetic' _chemical_formula_sum 'K.58 Na.42 (Si2.99 Al1.01) O8' _cell_length_a 8.434 _cell_length_b 13.015 _cell_length_c 7.1717 _cell_angle_alpha 90 _cell_angle_beta 116.09 _cell_angle_gamma 90 _cell_volume 707.012 _exptl_crystal_density_diffrn 2.551 _symmetry_space_group_name_H-M 'C 1 -1 1' loop_ _space_group_symop_operation_xyz 'x,y,z' '1/2+x,1/2+y,z' '-x,-y,-z' '1/2-x,1/2-y,-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_occupancy _atom_site_U_iso_or_equiv K1 0.27870 0.00000 0.13570 0.50000 0.02267 K2 0.28800 -0.00120 0.14160 0.08000 0.11905 Na1 0.28800 -0.00120 0.14160 0.42000 0.11905 Si1 0.00860 0.18160 0.22370 0.71000 0.01621 Al1 0.00860 0.18160 0.22370 0.29000 0.01621 Si2 0.00830 0.81830 0.22350 0.72000 0.01596 Al2 0.00830 0.81830 0.22350 0.28000 0.01596 Si3 0.70190 0.11700 0.34300 0.78000 0.01558 Al3 0.70190 0.11700 0.34300 0.22000 0.01558 Si4 0.70200 0.88280 0.34300 0.78000 0.01545 Al4 0.70200 0.88280 0.34300 0.22000 0.01545 O1 0.00000 0.14260 -0.00020 1.00000 0.02533 O2 0.61840 0.00020 0.28420 1.00000 0.02495 O3 0.82620 0.14110 0.22680 1.00000 0.02609 O4 0.82660 0.85880 0.22750 1.00000 0.02520 O5 0.02910 0.30810 0.25540 1.00000 0.02254 O6 0.02890 0.69220 0.25590 1.00000 0.02280 O7 0.18470 0.12610 0.40420 1.00000 0.02343 O8 0.18450 0.87430 0.40410 1.00000 0.02356