data_global _chemical_name_mineral 'Chevkinite-(Nd)' loop_ _publ_author_name 'Calvo C' 'Faggiani R' _journal_name_full 'American Mineralogist' _journal_volume 59 _journal_year 1974 _journal_page_first 1277 _journal_page_last 1285 _publ_section_title ; A re-investigation of the crystal structures of chevkinite and perrierite ; _database_code_amcsd 0000434 _chemical_compound_source 'natural, but location not given' _chemical_formula_sum 'Nd4 Si4 Co2 Ti3 O22' _cell_length_a 13.325 _cell_length_b 5.706 _cell_length_c 10.998 _cell_angle_alpha 90 _cell_angle_beta 100.82 _cell_angle_gamma 90 _cell_volume 821.339 _exptl_crystal_density_diffrn 5.268 _symmetry_space_group_name_H-M 'P 1 21/a 1' loop_ _space_group_symop_operation_xyz 'x,y,z' '1/2+x,1/2-y,z' '1/2-x,1/2+y,-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 Nd1 0.35651 0.01889 0.23426 1.00000 0.00990 Nd2 0.06955 -0.03317 0.24116 1.00000 0.00890 Si1 0.20080 0.49740 0.22980 1.00000 0.00530 Si2 0.35840 0.49930 0.04640 1.00000 0.00630 Co 0.00000 0.50000 0.00000 1.00000 0.00930 Ti1 0.24470 0.24560 0.50030 0.68000 0.01060 Co1 0.24470 0.24560 0.50030 0.32000 0.01060 Ti2a 0.00000 0.50000 0.50000 0.82000 0.01190 Co2a 0.00000 0.50000 0.50000 0.18000 0.01190 Ti2b 0.50000 0.50000 0.50000 0.82000 0.01290 Co2b 0.50000 0.50000 0.50000 0.18000 0.01290 O1 0.23840 -0.27250 0.31370 1.00000 0.00700 O11 0.21830 0.25950 0.31260 1.00000 0.00700 O21 -0.02540 0.25150 0.37210 1.00000 0.00800 O2 -0.02410 -0.25750 0.36970 1.00000 0.01200 O3 0.41340 -0.25500 0.09570 1.00000 0.01200 O31 0.44020 0.28800 0.09540 1.00000 0.01300 O5 0.15160 0.49590 0.50920 1.00000 0.00800 O4 0.14500 -0.01210 0.47520 1.00000 0.00700 O6 0.08330 0.54340 0.17370 1.00000 0.01000 O7 0.27050 0.45150 0.12470 1.00000 0.01300 O8 0.31490 -0.00970 -0.09920 1.00000 0.01100