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 Coordinates to O8 revised by Dr. Zhuming Yang, December 2001 ; _database_code_amcsd 0000433 _chemical_compound_source 'natural, but location not given' _chemical_formula_sum 'Nd4 Si4 Mg1.999 Ti3.001 O22' _cell_length_a 13.328 _cell_length_b 5.727 _cell_length_c 10.971 _cell_angle_alpha 90 _cell_angle_beta 100.91 _cell_angle_gamma 90 _cell_volume 822.275 _exptl_crystal_density_diffrn 4.982 _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 0.35442 0.02260 0.23312 1.00000 0.00950 Nd2 0.07127 -0.03662 0.24017 1.00000 0.00940 Si1 0.20150 0.49720 0.23060 1.00000 0.00690 Si2 0.35960 0.50190 0.04700 1.00000 0.00760 Mg 0.00000 0.50000 0.00000 1.00000 0.00780 Ti1 0.24340 0.24660 0.50000 0.68000 0.00820 Mg1 0.24340 0.24660 0.50000 0.32000 0.00820 Ti2a 0.00000 0.50000 0.50000 0.80700 0.01110 Mg2a 0.00000 0.50000 0.50000 0.19300 0.01110 Ti2b 0.50000 0.50000 0.50000 0.83400 0.00930 Mg2b 0.50000 0.50000 0.50000 0.16600 0.00930 O1 0.23930 -0.20980 0.31330 1.00000 0.00750 O11 0.21700 0.25270 0.31300 1.00000 0.00810 O2 -0.02470 -0.25270 0.37420 1.00000 0.00850 O21 -0.02140 0.24480 0.37360 1.00000 0.00930 O3 0.41310 -0.24930 0.09460 1.00000 0.00930 O31 0.44370 0.29470 0.09310 1.00000 0.01070 O4 0.14570 -0.01040 0.47570 1.00000 0.01060 O5 0.15110 0.50440 0.50990 1.00000 0.01050 O6 0.08660 0.54690 0.16860 1.00000 0.01130 O7 0.27410 0.44770 0.13070 1.00000 0.01510 O8 0.31320 0.48920 -0.09850 1.00000 0.00740