data_global _chemical_name_mineral 'Melilite' loop_ _publ_author_name 'Bindi L' 'Bonazzi P' _journal_name_full 'Physics and Chemistry of Minerals' _journal_volume 32 _journal_year 2005 _journal_page_first 89 _journal_page_last 96 _publ_section_title ; Incommensurate-normal phase transition in natural melilite: an in situ high-temperature X-ray single-crystal study Sample: San Venanzo, Italy; T = 413 K Note: xO1 and yO1 corrected by authors ; _database_code_amcsd 0008957 _chemical_formula_sum 'Ca1.87 Na.1 Sr.02 K.02 Mg.96 Al.09 Si1.98 O7' _cell_length_a 7.838 _cell_length_b 7.838 _cell_length_c 5.006 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 90 _cell_volume 307.540 _exptl_crystal_density_diffrn 2.950 _symmetry_space_group_name_H-M 'P -4 21 m' loop_ _space_group_symop_operation_xyz 'x,y,z' '1/2-y,1/2-x,z' 'y,-x,-z' '1/2-x,1/2+y,-z' '-x,-y,z' '1/2+y,1/2+x,z' '-y,x,-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 CaX 0.33190 0.16810 0.50570 0.93500 0.03720 NaX 0.33190 0.16810 0.50570 0.05000 0.03720 SrX 0.33190 0.16810 0.50570 0.01000 0.03720 KX 0.33190 0.16810 0.50570 0.01000 0.03720 MgT1 0.00000 0.00000 0.00000 0.96000 0.02930 AlT1 0.00000 0.00000 0.00000 0.07000 0.02930 SiT2 0.14010 0.35990 0.93470 0.99000 0.02770 AlT2 0.14010 0.35990 0.93470 0.01000 0.02770 O1 0.50000 0.00000 0.18130 1.00000 0.03870 O2 0.14110 0.35890 0.25420 1.00000 0.04120 O3 0.08040 0.18730 0.78620 1.00000 0.03800