data_global _chemical_name_mineral 'Phase-X' loop_ _publ_author_name 'Yang H' 'Konzett J' 'Prewitt C T' _journal_name_full 'American Mineralogist' _journal_volume 86 _journal_year 2001 _journal_page_first 1483 _journal_page_last 1488 _publ_section_title ; Crystal structure of phase X, a high pressure alkali-rich hydrous silicate and its anhydrous equivalent Sample: JKW56 ; _database_code_amcsd 0002745 _chemical_formula_sum 'K1.54 Mg1.92 Si2 O7' _cell_length_a 5.0812 _cell_length_b 5.0812 _cell_length_c 13.2112 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 120 _cell_volume 295.397 _exptl_crystal_density_diffrn 3.092 _symmetry_space_group_name_H-M 'P 63 c m' loop_ _space_group_symop_operation_xyz 'x,y,z' '-x,-x+y,z' 'x-y,x,1/2+z' '-y,-x,1/2+z' '-y,x-y,z' 'x-y,-y,z' '-x,-y,1/2+z' 'x,x-y,1/2+z' '-x+y,-x,z' 'y,x,z' 'y,-x+y,1/2+z' '-x+y,y,1/2+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 KA 0.33333 0.66667 0.20720 0.77000 0.01700 MgM 0.33333 0.66667 0.45410 0.96000 0.00800 Si1 0.00000 0.00000 0.07920 1.00000 0.00200 Si2 0.00000 0.00000 0.33470 1.00000 0.00800 O1 0.00000 0.00000 0.20560 1.00000 0.01000 O2 0.31020 0.00000 0.04580 1.00000 0.00900 O3 0.30810 0.00000 0.36340 1.00000 0.00600