data_global _amcsd_formula_title 'Nb Se3' loop_ _publ_author_name 'van Smaalen S' 'de Boer J' 'Meetsma A' 'Graafsma H' 'Sheu H' 'Darovskikh A' 'Coppens P' 'Levy F' _journal_name_full 'Physical Review' _journal_volume B45 _journal_year 1992 _journal_page_first 3103 _journal_page_last 3106 _publ_section_title ; Determination of the structural distortions corresponding to the q1- and q2-type modulations in niobium triselenide Nb Se3 _cod_database_code 1008952 ; _database_code_amcsd 0016818 _chemical_formula_sum 'Nb Se3' _cell_length_a 9.974 _cell_length_b 3.476 _cell_length_c 15.592 _cell_angle_alpha 90 _cell_angle_beta 109.4 _cell_angle_gamma 90 _cell_volume 509.877 _exptl_crystal_density_diffrn 6.444 _symmetry_space_group_name_H-M 'P 1 21/m 1' loop_ _space_group_symop_operation_xyz 'x,y,z' 'x,1/2-y,z' '-x,1/2+y,-z' '-x,-y,-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z Nb1 0.38580 0.25000 0.73260 Nb2 0.26150 0.75000 -0.05520 Nb3 0.37800 0.25000 0.08370 Se1 0.25390 0.75000 0.81320 Se2 0.46010 0.75000 0.62670 Se3 0.52120 0.75000 0.71740 Se4 0.12600 0.25000 -0.03930 Se5 0.22730 0.25000 0.04910 Se6 0.38810 0.25000 0.86030 Se7 0.25340 0.75000 0.17160 Se8 0.42460 0.75000 -0.01950 Se9 0.40990 0.75000 0.16580