#------------------------------------------------------------------------------ #$Date: 2016-03-22 22:45:02 +0000 (Tue, 22 Mar 2016) $ #$Revision: 179126 $ #$URL: svn://www.crystallography.net/cod/cif/4/30/88/4308824.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_4308824 loop_ _publ_author_name 'John A. Schlueter' 'Jamie L. Manson' 'Urs Geiser' _publ_section_title ; Structural and Magnetic Diversity in Tetraalkylammonium Salts of Anionic M[N(CN)2]3- (M= Mn and Ni) Three-Dimensional Coordination Polymers ; _journal_name_full 'Inorganic Chemistry' _journal_page_first 3194 _journal_page_last 3202 _journal_paper_doi 10.1021/ic0484598 _journal_volume 44 _journal_year 2005 _chemical_formula_moiety '(C20 H44 N, Ni, C6 N9)' _chemical_formula_sum 'C26 H44 N10 Ni' _chemical_formula_weight 555.42 _chemical_melting_point 436 _chemical_name_common ; Tetrapentylammonium nickel(II) dicyanamide ; _chemical_name_systematic ; Tetrapentylammonium nickel(II) dicyanamide ; _space_group_IT_number 52 _symmetry_cell_setting orthorhombic _symmetry_space_group_name_Hall '-P 2a 2bc' _symmetry_space_group_name_H-M 'P n n a' _atom_sites_solution_hydrogens geom _atom_sites_solution_primary direct _atom_sites_solution_secondary difmap _audit_creation_method SHELXL-97 _cell_angle_alpha 90.00 _cell_angle_beta 90.00 _cell_angle_gamma 90.00 _cell_formula_units_Z 4 _cell_length_a 12.9380(4) _cell_length_b 11.6233(4) _cell_length_c 19.8038(7) _cell_measurement_reflns_used 1960 _cell_measurement_temperature 298(2) _cell_measurement_theta_max 28.205 _cell_measurement_theta_min 2.571 _cell_volume 2978.14(17) _computing_cell_refinement 'SAINT (Bruker, 2001)' _computing_data_collection 'SMART (Siemens, 1995)' _computing_data_reduction 'SAINT (Bruker, 2001)' _computing_molecular_graphics 'SHELXTL (Sheldrick, 2001)' _computing_publication_material 'SHELXTL (Sheldrick, 2001)' _computing_structure_refinement 'SHELXTL (Sheldrick, 2001)' _computing_structure_solution 'SHELXTL (Sheldrick, 2001)' _diffrn_ambient_temperature 298(2) _diffrn_measured_fraction_theta_full 0.963 _diffrn_measured_fraction_theta_max 0.963 _diffrn_measurement_device_type 'Siemens SMART CCD area detector' _diffrn_measurement_method 'area detector \w scans' _diffrn_radiation_monochromator graphite _diffrn_radiation_source 'fine-focus sealed tube' _diffrn_radiation_type MoK\a _diffrn_radiation_wavelength 0.71073 _diffrn_reflns_av_R_equivalents 0.0320 _diffrn_reflns_av_sigmaI/netI 0.0242 _diffrn_reflns_limit_h_max 16 _diffrn_reflns_limit_h_min -16 _diffrn_reflns_limit_k_max 10 _diffrn_reflns_limit_k_min -15 _diffrn_reflns_limit_l_max 25 _diffrn_reflns_limit_l_min -26 _diffrn_reflns_number 19129 _diffrn_reflns_theta_full 28.25 _diffrn_reflns_theta_max 28.25 _diffrn_reflns_theta_min 1.88 _diffrn_standards_decay_% 0 _diffrn_standards_number 0 _exptl_absorpt_coefficient_mu 0.684 _exptl_absorpt_correction_T_max 0.888 _exptl_absorpt_correction_T_min 0.768 _exptl_absorpt_correction_type integration _exptl_absorpt_process_details ; (Sheldrick, 2001) ; _exptl_crystal_colour green _exptl_crystal_density_diffrn 1.239 _exptl_crystal_density_method 'not measured' _exptl_crystal_description block _exptl_crystal_F_000 1192 _exptl_crystal_size_max 0.60 _exptl_crystal_size_mid 0.24 _exptl_crystal_size_min 0.20 _refine_diff_density_max 0.448 _refine_diff_density_min -0.714 _refine_diff_density_rms 0.076 _refine_ls_extinction_method none _refine_ls_goodness_of_fit_ref 1.045 _refine_ls_hydrogen_treatment mixed _refine_ls_matrix_type full _refine_ls_number_parameters 173 _refine_ls_number_reflns 3564 _refine_ls_number_restraints 21 _refine_ls_restrained_S_all 1.051 _refine_ls_R_factor_all 0.0650 _refine_ls_R_factor_gt 0.0452 _refine_ls_shift/su_max 0.074 _refine_ls_shift/su_mean 0.002 _refine_ls_structure_factor_coef Fsqd _refine_ls_weighting_details ; calc w=1/[\s^2^(Fo^2^)+(0.0599P)^2^+1.9987P] where P=(Fo^2^+2Fc^2^)/3 ; _refine_ls_weighting_scheme calc _refine_ls_wR_factor_gt 0.1165 _refine_ls_wR_factor_ref 0.1304 _reflns_number_gt 2591 _reflns_number_total 3564 _reflns_threshold_expression >2sigma(I) _cod_data_source_file ic0484598si20041103_041216_9.cif _cod_data_source_block TPnANiDCART _cod_database_code 4308824 loop_ _symmetry_equiv_pos_as_xyz 'x, y, z' '-x+1/2, -y, z' '-x+1/2, y+1/2, -z+1/2' 'x, -y+1/2, -z+1/2' '-x, -y, -z' 'x-1/2, y, -z' 'x-1/2, -y-1/2, z-1/2' '-x, y-1/2, z-1/2' loop_ _atom_site_label _atom_site_type_symbol _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_U_iso_or_equiv _atom_site_adp_type _atom_site_occupancy _atom_site_symmetry_multiplicity _atom_site_calc_flag _atom_site_refinement_flags _atom_site_disorder_assembly _atom_site_disorder_group Ni1 Ni 0.2500 0.5000 0.597471(18) 0.03462(14) Uani 1 2 d S . . N1 N 0.17590(16) 0.59850(19) 0.52337(10) 0.0505(5) Uani 1 1 d . . . N2 N 0.19393(16) 0.61185(18) 0.67118(10) 0.0488(5) Uani 1 1 d . . . N3 N 0.11333(15) 0.40115(19) 0.59362(10) 0.0460(5) Uani 1 1 d . . . N4A N 0.046(4) 0.689(4) 0.451(5) 0.0366(7) Uiso 0.270(4) 1 d P . . N4B N 0.0580(14) 0.671(3) 0.4355(18) 0.0366(7) Uiso 0.40(6) 1 d P . . N4C N 0.0736(13) 0.637(2) 0.4214(9) 0.0366(7) Uiso 0.179(19) 1 d P . . N4D N 0.032(4) 0.6955(19) 0.463(2) 0.0366(7) Uiso 0.15(8) 1 d P . . N5A N 0.1190(6) 0.7364(10) 0.7587(7) 0.0408(12) Uiso 0.37(2) 1 d P . 1 N5B N 0.139(2) 0.782(2) 0.7263(14) 0.0408(12) Uiso 0.13(2) 1 d P . 2 C1 C 0.11516(19) 0.6287(2) 0.48549(13) 0.0489(6) Uani 1 1 d . . . C2 C 0.16703(18) 0.6792(2) 0.70898(12) 0.0441(5) Uani 1 1 d . . . C3 C 0.03415(19) 0.3705(2) 0.57533(12) 0.0463(5) Uani 1 1 d . . . N10 N -0.2500 0.0000 0.43291(17) 0.0524(7) Uani 1 2 d S . . C10 C -0.1540(2) 0.0117(2) 0.38924(15) 0.0596(7) Uani 1 1 d D B . H10A H -0.1569 0.0855 0.3664 0.071 Uiso 1 1 calc R . . H10B H -0.0941 0.0129 0.4187 0.071 Uiso 1 1 calc R . . C11 C -0.1378(3) -0.0807(3) 0.33670(19) 0.0788(9) Uani 1 1 d D . . H11A H -0.1999 -0.0867 0.3096 0.095 Uiso 1 1 calc R A 1 H11B H -0.1283 -0.1537 0.3596 0.095 Uiso 1 1 calc R A 1 C12A C -0.0459(5) -0.0612(6) 0.2896(3) 0.0808(8) Uiso 0.614(4) 1 d PD B 1 H12A H -0.0554 -0.1037 0.2479 0.097 Uiso 0.614(4) 1 calc PR B 1 H12B H -0.0394 0.0198 0.2788 0.097 Uiso 0.614(4) 1 calc PR B 1 C13A C 0.0495(4) -0.1028(6) 0.3257(3) 0.0808(8) Uiso 0.614(4) 1 d PD B 1 H13A H 0.0551 -0.0640 0.3689 0.097 Uiso 0.614(4) 1 calc PR B 1 H13B H 0.0435 -0.1847 0.3343 0.097 Uiso 0.614(4) 1 calc PR B 1 C14A C 0.1450(5) -0.0803(6) 0.2850(3) 0.0808(8) Uiso 0.614(4) 1 d PD B 1 H14A H 0.2024 -0.1203 0.3049 0.121 Uiso 0.614(4) 1 calc PR B 1 H14B H 0.1591 0.0008 0.2845 0.121 Uiso 0.614(4) 1 calc PR B 1 H14C H 0.1348 -0.1070 0.2397 0.121 Uiso 0.614(4) 1 calc PR B 1 C12B C -0.0178(7) -0.0579(9) 0.3193(5) 0.0808(8) Uiso 0.386(4) 1 d PD B 2 H12C H -0.0095 0.0191 0.3013 0.097 Uiso 0.386(4) 1 calc PR B 2 H12D H 0.0233 -0.0639 0.3601 0.097 Uiso 0.386(4) 1 calc PR B 2 C13B C 0.0184(7) -0.1429(8) 0.2694(5) 0.0808(8) Uiso 0.386(4) 1 d PD B 2 H13C H -0.0243 -0.1374 0.2293 0.097 Uiso 0.386(4) 1 calc PR B 2 H13D H 0.0095 -0.2195 0.2880 0.097 Uiso 0.386(4) 1 calc PR B 2 C14B C 0.1318(7) -0.1271(9) 0.2492(5) 0.0808(8) Uiso 0.386(4) 1 d PD B 2 H14D H 0.1625 -0.2010 0.2408 0.121 Uiso 0.386(4) 1 calc PR B 2 H14E H 0.1684 -0.0893 0.2850 0.121 Uiso 0.386(4) 1 calc PR B 2 H14F H 0.1356 -0.0812 0.2089 0.121 Uiso 0.386(4) 1 calc PR B 2 C15 C -0.2449(2) -0.1083(2) 0.47588(14) 0.0600(7) Uani 1 1 d D . . H15A H -0.3084 -0.1140 0.5016 0.072 Uiso 1 1 calc R . . H15B H -0.2421 -0.1742 0.4459 0.072 Uiso 1 1 calc R . . C16 C -0.1546(3) -0.1161(3) 0.52465(17) 0.0780(10) Uani 1 1 d D . . H16A H -0.1533 -0.0487 0.5535 0.094 Uiso 1 1 calc R . . H16B H -0.0901 -0.1193 0.4998 0.094 Uiso 1 1 calc R . . C17 C -0.1669(3) -0.2243(3) 0.56748(16) 0.0680(8) Uani 1 1 d D . . H17A H -0.2321 -0.2198 0.5915 0.082 Uiso 1 1 calc R . . H17B H -0.1702 -0.2903 0.5376 0.082 Uiso 1 1 calc R . . C18 C -0.0828(3) -0.2435(3) 0.6174(2) 0.0862(11) Uani 1 1 d D . . H18A H -0.0804 -0.1791 0.6485 0.103 Uiso 1 1 calc R . . H18B H -0.0171 -0.2471 0.5940 0.103 Uiso 1 1 calc R . . C19 C -0.0987(3) -0.3535(4) 0.6567(2) 0.1090(15) Uani 1 1 d D . . H19A H -0.0433 -0.3630 0.6885 0.164 Uiso 1 1 calc R . . H19B H -0.0997 -0.4176 0.6262 0.164 Uiso 1 1 calc R . . H19C H -0.1632 -0.3498 0.6806 0.164 Uiso 1 1 calc R . . loop_ _atom_site_aniso_label _atom_site_aniso_U_11 _atom_site_aniso_U_22 _atom_site_aniso_U_33 _atom_site_aniso_U_23 _atom_site_aniso_U_13 _atom_site_aniso_U_12 Ni1 0.0337(2) 0.0376(2) 0.0326(2) 0.000 0.000 -0.00220(16) N1 0.0444(11) 0.0550(12) 0.0521(12) 0.0104(10) -0.0068(9) -0.0072(10) N2 0.0465(12) 0.0527(12) 0.0474(11) -0.0097(10) 0.0034(9) -0.0013(9) N3 0.0406(11) 0.0514(12) 0.0461(11) 0.0044(9) -0.0009(8) -0.0060(9) C1 0.0435(13) 0.0467(13) 0.0565(14) 0.0146(11) -0.0057(11) -0.0149(11) C2 0.0421(12) 0.0436(12) 0.0465(12) -0.0050(11) -0.0011(10) -0.0033(10) C3 0.0460(13) 0.0452(13) 0.0478(12) 0.0163(11) -0.0048(10) -0.0062(11) N10 0.0571(18) 0.0446(16) 0.0555(18) 0.000 0.000 -0.0149(14) C10 0.0550(16) 0.0562(16) 0.0675(17) 0.0041(13) 0.0045(13) -0.0133(13) C11 0.079(2) 0.0651(19) 0.092(2) -0.0094(18) 0.0197(19) -0.0053(17) C15 0.0722(18) 0.0489(14) 0.0588(16) 0.0050(12) -0.0036(14) -0.0178(13) C16 0.086(2) 0.0649(19) 0.083(2) 0.0104(16) -0.0230(18) -0.0227(17) C17 0.0737(19) 0.0654(18) 0.0649(18) 0.0018(15) -0.0099(15) -0.0123(16) C18 0.083(2) 0.084(2) 0.091(2) 0.013(2) -0.023(2) -0.015(2) C19 0.096(3) 0.104(3) 0.126(4) 0.046(3) -0.026(3) -0.007(2) loop_ _atom_type_symbol _atom_type_description _atom_type_scat_dispersion_real _atom_type_scat_dispersion_imag _atom_type_scat_source C C 0.0033 0.0016 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4' H H 0.0000 0.0000 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4' N N 0.0061 0.0033 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4' Ni Ni 0.3393 1.1124 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4' loop_ _geom_angle_atom_site_label_1 _geom_angle_atom_site_label_2 _geom_angle_atom_site_label_3 _geom_angle _geom_angle_site_symmetry_1 _geom_angle_site_symmetry_3 _geom_angle_publ_flag N2 Ni1 N2 91.13(12) 2_565 . ? N2 Ni1 N1 172.31(8) . 2_565 ? N2 Ni1 N1 89.45(9) . . ? N1 Ni1 N1 91.00(12) 2_565 . ? N2 Ni1 N3 88.70(8) . 2_565 ? N1 Ni1 N3 93.48(8) . 2_565 ? N2 Ni1 N3 94.20(8) . . ? N1 Ni1 N3 83.61(8) . . ? N3 Ni1 N3 175.86(10) 2_565 . ? C1 N1 Ni1 160.7(2) . . ? C2 N2 Ni1 175.0(2) . . ? C3 N3 Ni1 158.72(19) . . ? C1 N4A C3 116(2) . 5_566 ? C3 N4B C1 119.4(6) 5_566 . ? C1 N4C C3 110.0(13) . 5_566 ? C3 N4D C1 110(2) 5_566 . ? C2 N5A C2 120.3(4) 4_566 . ? C2 N5B C2 117.5(15) . 4_566 ? N1 C1 N4A 165(4) . . ? N1 C1 N4B 170.2(9) . . ? N1 C1 N4C 153.2(12) . . ? N1 C1 N4D 155.2(19) . . ? N2 C2 N5B 153.4(15) . . ? N2 C2 N5A 165.9(5) . 4_566 ? N2 C2 N5A 165.1(5) . . ? N2 C2 N5B 153.9(14) . 4_566 ? N3 C3 N4B 170.5(10) . 5_566 ? N3 C3 N4A 166(4) . 5_566 ? N3 C3 N4D 155(2) . 5_566 ? N3 C3 N4C 153.8(11) . 5_566 ? C10 N10 C10 110.6(3) 2_455 . ? C10 N10 C15 106.24(15) . 2_455 ? C10 N10 C15 110.92(16) . . ? C15 N10 C15 112.0(3) 2_455 . ? C11 C10 N10 116.2(2) . . ? C11 C10 H10A 108.2 . . ? N10 C10 H10A 108.2 . . ? C11 C10 H10B 108.2 . . ? N10 C10 H10B 108.2 . . ? H10A C10 H10B 107.4 . . ? C10 C11 C12A 115.0(4) . . ? C10 C11 C12B 99.4(4) . . ? C10 C11 H11A 108.5 . . ? C12A C11 H11A 108.5 . . ? C10 C11 H11B 108.5 . . ? C12A C11 H11B 108.5 . . ? C12B C11 H11B 97.1 . . ? H11A C11 H11B 107.5 . . ? C13A C12A C11 107.4(5) . . ? C13A C12A H12A 110.2 . . ? C11 C12A H12A 110.2 . . ? C13A C12A H12B 110.2 . . ? C11 C12A H12B 110.2 . . ? H12A C12A H12B 108.5 . . ? C14A C13A C12A 111.4(5) . . ? C14A C13A H13A 109.4 . . ? C12A C13A H13A 109.4 . . ? C14A C13A H13B 109.4 . . ? C12A C13A H13B 109.4 . . ? H13A C13A H13B 108.0 . . ? C13A C14A H14A 109.5 . . ? C13A C14A H14B 109.5 . . ? H14A C14A H14B 109.5 . . ? C13A C14A H14C 109.5 . . ? H14A C14A H14C 109.5 . . ? H14B C14A H14C 109.5 . . ? C13B C12B C11 109.8(7) . . ? C13B C12B H12C 109.7 . . ? C11 C12B H12C 109.7 . . ? C13B C12B H12D 109.7 . . ? C11 C12B H12D 109.7 . . ? H12C C12B H12D 108.2 . . ? C12B C13B C14B 113.6(8) . . ? C12B C13B H13C 108.9 . . ? C14B C13B H13C 108.9 . . ? C12B C13B H13D 108.9 . . ? C14B C13B H13D 108.9 . . ? H13C C13B H13D 107.7 . . ? C13B C14B H14D 109.5 . . ? C13B C14B H14E 109.5 . . ? H14D C14B H14E 109.5 . . ? C13B C14B H14F 109.5 . . ? H14D C14B H14F 109.5 . . ? H14E C14B H14F 109.5 . . ? C16 C15 N10 116.0(2) . . ? C16 C15 H15A 108.3 . . ? N10 C15 H15A 108.3 . . ? C16 C15 H15B 108.3 . . ? N10 C15 H15B 108.3 . . ? H15A C15 H15B 107.4 . . ? C15 C16 C17 108.9(2) . . ? C15 C16 H16A 109.9 . . ? C17 C16 H16A 109.9 . . ? C15 C16 H16B 109.9 . . ? C17 C16 H16B 109.9 . . ? H16A C16 H16B 108.3 . . ? C18 C17 C16 114.7(3) . . ? C18 C17 H17A 108.6 . . ? C16 C17 H17A 108.6 . . ? C18 C17 H17B 108.6 . . ? C16 C17 H17B 108.6 . . ? H17A C17 H17B 107.6 . . ? C17 C18 C19 111.8(3) . . ? C17 C18 H18A 109.3 . . ? C19 C18 H18A 109.3 . . ? C17 C18 H18B 109.3 . . ? C19 C18 H18B 109.3 . . ? H18A C18 H18B 107.9 . . ? C18 C19 H19A 109.5 . . ? C18 C19 H19B 109.5 . . ? H19A C19 H19B 109.5 . . ? C18 C19 H19C 109.5 . . ? H19A C19 H19C 109.5 . . ? H19B C19 H19C 109.5 . . ? loop_ _geom_bond_atom_site_label_1 _geom_bond_atom_site_label_2 _geom_bond_distance _geom_bond_site_symmetry_2 _geom_bond_publ_flag Ni1 N2 2.085(2) . ? Ni1 N1 2.094(2) . ? Ni1 N3 2.110(2) . ? N1 C1 1.142(3) . ? N2 C2 1.137(3) . ? N3 C3 1.143(3) . ? N4A C1 1.33(2) . ? N4A C3 1.35(2) 5_566 ? N4B C3 1.305(8) 5_566 ? N4B C1 1.331(9) . ? N4C C1 1.381(13) . ? N4C C3 1.398(16) 5_566 ? N4D C3 1.38(2) 5_566 ? N4D C1 1.40(3) . ? N5A C2 1.326(10) 4_566 ? N5A C2 1.341(9) . ? N5B C2 1.300(19) . ? N5B C2 1.41(2) 4_566 ? C2 N5A 1.326(10) 4_566 ? C2 N5B 1.41(2) 4_566 ? C3 N4B 1.305(8) 5_566 ? C3 N4A 1.35(2) 5_566 ? C3 N4D 1.38(2) 5_566 ? C3 N4C 1.398(16) 5_566 ? N10 C10 1.520(3) 2_455 ? N10 C10 1.520(3) . ? N10 C15 1.521(3) 2_455 ? N10 C15 1.521(3) . ? C10 C11 1.511(4) . ? C10 H10A 0.9700 . ? C10 H10B 0.9700 . ? C11 C12A 1.528(6) . ? C11 C12B 1.612(9) . ? C11 H11A 0.9700 . ? C11 H11B 0.9700 . ? C12A C13A 1.506(8) . ? C12A H12A 0.9700 . ? C12A H12B 0.9700 . ? C13A C14A 1.498(7) . ? C13A H13A 0.9700 . ? C13A H13B 0.9700 . ? C14A H14A 0.9600 . ? C14A H14B 0.9600 . ? C14A H14C 0.9600 . ? C12B C13B 1.473(11) . ? C12B H12C 0.9700 . ? C12B H12D 0.9700 . ? C13B C14B 1.532(11) . ? C13B H13C 0.9700 . ? C13B H13D 0.9700 . ? C14B H14D 0.9600 . ? C14B H14E 0.9600 . ? C14B H14F 0.9600 . ? C15 C16 1.518(4) . ? C15 H15A 0.9700 . ? C15 H15B 0.9700 . ? C16 C17 1.525(4) . ? C16 H16A 0.9700 . ? C16 H16B 0.9700 . ? C17 C18 1.487(4) . ? C17 H17A 0.9700 . ? C17 H17B 0.9700 . ? C18 C19 1.511(5) . ? C18 H18A 0.9700 . ? C18 H18B 0.9700 . ? C19 H19A 0.9600 . ? C19 H19B 0.9600 . ? C19 H19C 0.9600 . ? loop_ _geom_torsion_atom_site_label_1 _geom_torsion_atom_site_label_2 _geom_torsion_atom_site_label_3 _geom_torsion_atom_site_label_4 _geom_torsion _geom_torsion_site_symmetry_1 _geom_torsion_site_symmetry_2 _geom_torsion_site_symmetry_3 _geom_torsion_site_symmetry_4 _geom_torsion_publ_flag C10 N10 C10 C11 -53.6(2) 2_455 . . . ? C15 N10 C10 C11 -174.1(3) 2_455 . . . ? C15 N10 C10 C11 64.0(4) . . . . ? N10 C10 C11 C12A 175.0(3) . . . . ? N10 C10 C11 C12B -164.1(5) . . . . ? C10 C11 C12A C13A 82.5(6) . . . . ? C11 C12A C13A C14A -176.4(5) . . . . ? C10 C11 C12B C13B 177.9(7) . . . . ? C11 C12B C13B C14B 179.4(7) . . . . ? C10 N10 C15 C16 -179.6(3) 2_455 . . . ? C10 N10 C15 C16 60.1(4) . . . . ? C15 N10 C15 C16 -58.4(2) 2_455 . . . ? N10 C15 C16 C17 175.1(3) . . . . ? C15 C16 C17 C18 179.5(3) . . . . ? C16 C17 C18 C19 -178.6(4) . . . . ?