data_global _chemical_name_mineral 'Nierite' loop_ _publ_author_name 'Billy M' 'Labbe J' 'Selvaraj A' 'Roult G' _journal_name_full 'Materials Research Bulletin' _journal_volume 18 _journal_year 1983 _journal_page_first 921 _journal_page_last 934 _publ_section_title ; Modifications structurales du nitrure de silicium en fonction de la temperature _cod_database_code 1001248 ; _database_code_amcsd 0014311 _chemical_formula_sum 'N4 Si3' _cell_length_a 7.6322 _cell_length_b 7.6322 _cell_length_c 2.9191 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 120 _cell_volume 147.258 _exptl_crystal_density_diffrn 3.164 _symmetry_space_group_name_H-M 'P 63/m' loop_ _space_group_symop_operation_xyz 'x,y,z' '-x+y,-x,1/2-z' 'x-y,x,1/2+z' 'y,-x+y,-z' '-y,x-y,z' 'x,y,1/2-z' '-x,-y,1/2+z' 'x-y,x,-z' '-x+y,-x,z' '-y,x-y,1/2-z' 'y,-x+y,1/2+z' '-x,-y,-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z N1 0.33333 0.66667 0.25000 N2 0.33940 0.03620 0.25000 Si1 0.19520 0.76560 0.25000