data_global _chemical_name_mineral 'Pigeonite' loop_ _publ_author_name 'Domeneghetti M C' 'Zema M' 'Tazzoli V' _journal_name_full 'American Mineralogist' _journal_volume 90 _journal_year 2005 _journal_page_first 1816 _journal_page_last 1823 _publ_section_title ; Kinetics of Fe2+-Mg order-disorder in P2_1/c pigeonite Sample: N.13, annealed at T = 750 C for t = 50 min ; _database_code_amcsd 0003990 _chemical_compound_source 'Parana, Brazil' _chemical_formula_sum 'Mg.918 Fe.85 Ca.191 Mn.029 Na.003 Ti.01 Si1.984 Al.016 O6' _cell_length_a 9.7100 _cell_length_b 8.9462 _cell_length_c 5.2480 _cell_angle_alpha 90 _cell_angle_beta 108.494 _cell_angle_gamma 90 _cell_volume 432.338 _exptl_crystal_density_diffrn 3.560 _symmetry_space_group_name_H-M 'P 1 21/c 1' loop_ _space_group_symop_operation_xyz 'x,y,z' 'x,1/2-y,1/2+z' '-x,1/2+y,1/2-z' '-x,-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 MgM2A 0.25540 0.01701 0.22780 0.18530 ? FeM2A 0.25540 0.01701 0.22780 0.59530 ? CaM2A 0.25540 0.01701 0.22780 0.09050 ? MnM2A 0.25540 0.01701 0.22780 0.02540 ? NaM2A 0.25540 0.01701 0.22780 0.00300 ? CaM2B 0.25414 0.05065 0.25038 0.10050 0.01177 MgM1 0.25047 0.65456 0.23135 0.73230 ? Fe2+M1 0.25047 0.65456 0.23135 0.23930 ? Fe3+M1 0.25047 0.65456 0.23135 0.01490 ? TiM1 0.25047 0.65456 0.23135 0.01010 ? MnM1 0.25047 0.65456 0.23135 0.00350 ? SiA 0.04277 0.34052 0.27720 1.00000 ? SiB 0.54951 0.83741 0.23856 0.98400 ? AlB 0.54951 0.83741 0.23856 0.01600 ? O1A 0.86766 0.33836 0.16954 1.00000 ? O2A 0.12169 0.49940 0.33193 1.00000 ? O3A 0.10394 0.26197 0.57830 1.00000 ? O1B 0.37389 0.83679 0.13480 1.00000 ? O2B 0.62904 0.98729 0.37329 1.00000 ? O3B 0.60480 0.70891 0.48057 1.00000 ? loop_ _atom_site_aniso_label _atom_site_aniso_U_11 _atom_site_aniso_U_22 _atom_site_aniso_U_33 _atom_site_aniso_U_12 _atom_site_aniso_U_13 _atom_site_aniso_U_23 MgM2A 0.01035 0.01186 0.00718 0.00064 0.00071 0.00184 FeM2A 0.01035 0.01186 0.00718 0.00064 0.00071 0.00184 CaM2A 0.01035 0.01186 0.00718 0.00064 0.00071 0.00184 MnM2A 0.01035 0.01186 0.00718 0.00064 0.00071 0.00184 NaM2A 0.01035 0.01186 0.00718 0.00064 0.00071 0.00184 MgM1 0.00820 0.00712 0.00792 0.00014 0.00257 0.00040 Fe2+M1 0.00820 0.00712 0.00792 0.00014 0.00257 0.00040 Fe3+M1 0.00820 0.00712 0.00792 0.00014 0.00257 0.00040 TiM1 0.00820 0.00712 0.00792 0.00014 0.00257 0.00040 MnM1 0.00820 0.00712 0.00792 0.00014 0.00257 0.00040 SiA 0.00616 0.00659 0.00996 -0.00049 0.00353 -0.00061 SiB 0.00662 0.00644 0.00790 -0.00101 0.00276 -0.00089 AlB 0.00662 0.00644 0.00790 -0.00101 0.00276 -0.00089 O1A 0.00704 0.00982 0.00980 0.00019 0.00275 -0.00016 O2A 0.01247 0.00883 0.01361 -0.00316 0.00587 -0.00125 O3A 0.00853 0.02239 0.02048 0.00078 0.00447 0.01350 O1B 0.00735 0.01050 0.00967 0.00021 0.00300 -0.00026 O2B 0.01464 0.01215 0.02089 -0.00573 0.01002 -0.00723 O3B 0.00759 0.02018 0.01344 0.00052 0.00316 0.00779