data_global _chemical_name_mineral 'Pigeonite' loop_ _publ_author_name 'Camara F' 'Carpenter M A' 'Domeneghetti M C' 'Tazzoli V' _journal_name_full 'Physics and Chemistry of Minerals' _journal_volume 29 _journal_year 2002 _journal_page_first 331 _journal_page_last 340 _publ_section_title ; Non-convergent ordering and displacive phase transition in pigeonite: in situ HT XRD study Sample: hga, T = 25 C ; _database_code_amcsd 0008637 _chemical_compound_source 'from rhyodacite, Parana, Brazil' _chemical_formula_sum '(Mg.463 Fe.416 Mn.014 Ca.107) Si O3' _cell_length_a 9.719 _cell_length_b 8.947 _cell_length_c 5.251 _cell_angle_alpha 90 _cell_angle_beta 108.49 _cell_angle_gamma 90 _cell_volume 433.035 _exptl_crystal_density_diffrn 3.547 _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 MgM1 0.25060 0.65480 0.23170 0.76680 0.00600 FeM1 0.25060 0.65480 0.23170 0.20820 0.00600 MnM1 0.25060 0.65480 0.23170 0.00670 0.00600 CaM1 0.25060 0.65480 0.23170 0.01830 0.00600 MgM2 0.25520 0.01920 0.22940 0.15960 0.01100 FeM2 0.25520 0.01920 0.22940 0.62450 0.01100 MnM2 0.25520 0.01920 0.22940 0.02060 0.01100 CaM2 0.25520 0.01920 0.22940 0.19530 0.01100 SiA 0.04260 0.34050 0.27610 1.00000 0.00700 SiB 0.54930 0.83740 0.23820 1.00000 0.00600 O1A 0.86730 0.33830 0.16850 1.00000 0.00900 O1B 0.37350 0.83670 0.13420 1.00000 0.00900 O2A 0.12150 0.49940 0.33160 1.00000 0.01100 O2B 0.62860 0.98810 0.37190 1.00000 0.01400 O3A 0.10420 0.26050 0.57580 1.00000 0.01700 O3B 0.60500 0.71000 0.48060 1.00000 0.01300 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 MgM1 0.00700 0.00600 0.00700 0.00000 0.00300 0.00000 FeM1 0.00700 0.00600 0.00700 0.00000 0.00300 0.00000 MnM1 0.00700 0.00600 0.00700 0.00000 0.00300 0.00000 CaM1 0.00700 0.00600 0.00700 0.00000 0.00300 0.00000 MgM2 0.00900 0.01600 0.00800 0.00100 0.00100 0.00300 FeM2 0.00900 0.01600 0.00800 0.00100 0.00100 0.00300 MnM2 0.00900 0.01600 0.00800 0.00100 0.00100 0.00300 CaM2 0.00900 0.01600 0.00800 0.00100 0.00100 0.00300 SiA 0.00600 0.00600 0.01000 -0.00100 0.00400 -0.00100 SiB 0.00600 0.00500 0.00800 -0.00100 0.00300 -0.00100 O1A 0.00700 0.00900 0.01000 0.00000 0.00200 0.00000 O1B 0.00700 0.00900 0.01100 0.00000 0.00300 0.00100 O2A 0.01200 0.00700 0.01400 -0.02600 0.00600 -0.00100 O2B 0.01400 0.01100 0.02100 -0.00600 0.01100 -0.00800 O3A 0.00700 0.02200 0.02100 0.00200 0.00400 0.01300 O3B 0.00800 0.01700 0.01400 0.00000 0.00300 0.00600