#------------------------------------------------------------------------------ #$Date: 2008-01-14 00:15:36 +0200 (Mon, 14 Jan 2008) $ #$Revision: 14 $ #$URL: file:///home/coder/svn-repositories/cod/cif/2/2003053.cif $ #------------------------------------------------------------------------------ # # This file is available in the Crystallography Open Database (COD), # http://www.crystallography.net/ # # All data on this site have been placed in the public domain by the # contributors. # data_2003053 _journal_name_full 'Acta Crystallographica, Section B' _journal_year 1999 _journal_volume B55 _journal_page_first 78 _journal_page_last 84 _publ_section_title ; Experimental Charge Density and Electrostatic Potential in Nicotinamide ; loop_ _publ_author_name 'YOSHIHISA MIWA' 'TAKASHI MIZUNO' 'KAZUNORI TSUCHIDA' 'TOORU TAGA' 'YUTAKA IWATA' _publ_section_synopsis ; The accurate crystal structure of nicotinamide was determined from the X-ray and the neutron diffraction experiments. The electron distribution determined by the maximum entropy method show that the electrostatic properties depend on the rotation of carboxyamide group for the pyridine plane. ; _chemical_name_common nicotinamide _chemical_formula_sum 'C6 H6 N2 O1' _chemical_formula_weight 122.13 _symmetry_cell_setting monoclinic _symmetry_space_group_name_H-M P21/c loop_ _symmetry_equiv_pos_as_xyz '+X,+Y,+Z' '-X,1/2+Y,1/2-Z' _cell_length_a 3.975(5) _cell_length_b 15.632(8) _cell_length_c 9.422(4) _cell_angle_alpha 90 _cell_angle_beta 99.03(7) _cell_angle_gamma 90 _cell_volume 578.2 _cell_formula_units_Z 4 _cell_measurement_temperature 295 _exptl_crystal_description ? _exptl_crystal_colour colorless _exptl_crystal_size_max 6.0 _exptl_crystal_size_mid 4.0 _exptl_crystal_size_min 4.0 _exptl_crystal_density_diffrn 1.4028 _exptl_crystal_density_meas 1.398 _exptl_crystal_density_method floatation _exptl_absorpt_coefficient_mu 0.827 _exptl_absorpt_correction_type none _diffrn_ambient_temperature 295 _diffrn_radiation_type neutron _diffrn_radiation_wavelength 1.005(3) _diffrn_radiation_source KUR _diffrn_radiation_monochromator Cu(220) _diffrn_measurement_device 'four-circle' _diffrn_measurement_method \w/2\q _diffrn_reflns_number 1748 _diffrn_reflns_av_R_equivalents 0.022 _diffrn_reflns_theta_min 1 _diffrn_reflns_theta_max 45 _diffrn_reflns_limit_h_min 0 _diffrn_reflns_limit_h_max 5 _diffrn_reflns_limit_k_min 0 _diffrn_reflns_limit_k_max 17 _diffrn_reflns_limit_l_min -10 _diffrn_reflns_limit_l_max 10 _diffrn_reflns_reduction_process ? _diffrn_standards_number 1 _diffrn_standards_interval_count 200 _diffrn_standards_decay_% 1.5 _reflns_number_total 1739 _reflns_number_observed 1026 _reflns_observed_criterion F>3\s(F) _refine_ls_structure_factor_coef F _refine_ls_matrix_type 'Full-matrix least-squares' _refine_ls_R_factor_obs 0.060 _refine_ls_wR_factor_obs 0.068 _refine_ls_number_reflns 1026 _refine_ls_number_parameters 137 _refine_ls_hydrogen_treatment 'refall' _refine_ls_weighting_scheme 'w=1/[\s^2^(F)+0.04F^2^]' _refine_ls_shift/esd_max 0.01 _refine_ls_extinction_method 'Zachariasen (1967) approximation' loop_ _atom_type_symbol C H N O loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_U_iso_or_equiv _atom_site_thermal_displace_type C2 -0.0309(2) 0.33933(5) 0.19415(8) .0392(2) Ueq C3 0.1567(2) 0.35806(5) 0.32705(7) .0335(2) Ueq C4 0.1769(3) 0.44289(5) 0.37108(9) .0467(3) Ueq C5 0.0186(3) 0.50563(6) 0.28040(10) .0535(3) Ueq C6 -0.1626(3) 0.48076(5) 0.14954(9) .0476(3) Ueq C7 0.3326(2) 0.29247(5) 0.42746(7) .0385(2) Ueq N1 -0.1911(2) 0.39919(4) 0.10646(6) .0444(2) Ueq N2 0.4113(2) 0.21779(4) 0.37183(6) .0474(2) Ueq O1 0.4022(3) 0.30864(7) 0.55649(9) .0521(3) Ueq H2 -0.0645(6) 0.27470(10) 0.1560(2) .0653(7) Ueq H4 0.3135(8) 0.45780(10) 0.4781(2) .0833(9) Ueq H5 0.0309(9) 0.5724(2) 0.3109(3) .0940(10) Ueq H6 -0.2889(8) 0.52780(10) 0.0762(3) .0798(9) Ueq H2A 0.3942(6) 0.20970(10) 0.2656(2) .0614(6) Ueq H2B 0.5358(6) 0.17330(10) 0.4388(2) .0624(6) Ueq loop_ _atom_site_aniso_label _atom_site_aniso_u_11 _atom_site_aniso_u_22 _atom_site_aniso_u_33 _atom_site_aniso_u_12 _atom_site_aniso_u_13 _atom_site_aniso_u_23 C2 .0499(4) .0371(4) .0288(4) -.0019(3) .0002(3) -.0018(3) C3 .0400(4) .0340(4) .0257(3) -.0045(3) .0024(3) -.0005(2) C4 .0574(5) .0409(5) .0381(4) -.0078(4) -.0041(4) -.0058(3) C5 .0707(6) .0359(5) .0521(5) .0021(4) .0035(4) -.0014(3) C6 .0632(6) .0369(5) .0421(4) .0049(4) .0059(4) .0025(3) C7 .0488(4) .0414(4) .0236(4) -.0034(3) .0006(3) .0011(2) N1 .0539(4) .0441(4) .0321(3) .0033(2) -.0025(2) .0015(2) N2 .0663(4) .0403(2) .0330(3) .0035(3) -.0001(2) .0021(2) O1 .0737(7) .0546(6) .0256(4) .0007(5) .0007(4) .0000(4) H2 .0920(10) .0490(10) .0477(8) .0002(9) -.0088(9) -.0088(7) H4 .118(2) .0640(10) .0590(10) -.0140(10) -.0160(10) -.0144(9) H5 .137(2) .0500(10) .086(2) .0020(10) -.011(2) -.0060(10) H6 .117(2) .0470(10) .0700(10) .0150(10) -.0010(10) .0109(8) H2A .0860(10) .0550(10) .0417(9) .0060(10) .0080(8) -.0032(7) H2B .0800(10) .0540(10) .0491(9) .0007(9) -.0037(8) .0079(7)