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 434 _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 90.0 _cell_angle_beta 100.82 _cell_angle_gamma 90.0 _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 1.0 0.0099 Nd2 0.06955 -0.03317 0.24116 1.0 0.0089 Si1 0.2008 0.4974 0.2298 1.0 0.0053 Si2 0.3584 0.4993 0.0464 1.0 0.0063 Co 0.0 0.5 0.0 1.0 0.0093 Ti1 0.2447 0.2456 0.5003 0.68 0.0106 Co1 0.2447 0.2456 0.5003 0.32 0.0106 Ti2a 0.0 0.5 0.5 0.82 0.0119 Co2a 0.0 0.5 0.5 0.18 0.0119 Ti2b 0.5 0.5 0.5 0.82 0.0129 Co2b 0.5 0.5 0.5 0.18 0.0129 O1 0.2384 -0.2725 0.3137 1.0 0.007 O11 0.2183 0.2595 0.3126 1.0 0.007 O21 -0.0254 0.2515 0.3721 1.0 0.008 O2 -0.0241 -0.2575 0.3697 1.0 0.012 O3 0.4134 -0.255 0.0957 1.0 0.012 O31 0.4402 0.288 0.0954 1.0 0.013 O5 0.1516 0.4959 0.5092 1.0 0.008 O4 0.145 -0.0121 0.4752 1.0 0.007 O6 0.0833 0.5434 0.1737 1.0 0.01 O7 0.2705 0.4515 0.1247 1.0 0.013 O8 0.3149 -0.0097 -0.0992 1.0 0.011