#------------------------------------------------------------------------------
#$Date: 2016-02-20 22:30:07 +0200 (Sat, 20 Feb 2016) $
#$Revision: 176789 $
#$URL: svn://www.crystallography.net/cod/cif/2/22/16/2221637.cif $
#------------------------------------------------------------------------------
#
# This file is available in the Crystallography Open Database (COD),
# http://www.crystallography.net/. The original data for this entry
# were provided by IUCr Journals, http://journals.iucr.org/.
#
# The file may be used within the scientific community so long as
# proper attribution is given to the journal article from which the
# data were obtained.
#
data_2221637
loop_
_publ_author_name
'Li, Hongjuan'
'Sun, Jufeng'
'Dai, Xianping'
_publ_section_title
;
 Tetrakis(1-benzyl-1H-imidazole)dichloridonickel(II)
;
_journal_coeditor_code           CV2549
_journal_issue                   5
_journal_name_full               'Acta Crystallographica Section E'
_journal_page_first              m564
_journal_paper_doi               10.1107/S1600536809014494
_journal_volume                  65
_journal_year                    2009
_chemical_formula_iupac          '[Ni Cl2 (C10 H10 N2)4]'
_chemical_formula_moiety         'C40 H40 Cl2 N8 Ni'
_chemical_formula_sum            'C40 H40 Cl2 N8 Ni'
_chemical_formula_weight         762.41
_chemical_name_systematic
;
Tetrakis(1-benzyl-1H-imidazole)dichloridonickel(II)
;
_space_group_IT_number           61
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  '-P 2ac 2ab'
_symmetry_space_group_name_H-M   'P b c 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                   7.296(3)
_cell_length_b                   17.117(4)
_cell_length_c                   29.651(3)
_cell_measurement_reflns_used    20
_cell_measurement_temperature    292(2)
_cell_measurement_theta_max      6.91
_cell_measurement_theta_min      5.69
_cell_volume                     3703.0(18)
_computing_cell_refinement       'DIFRAC (Gabe & White, 1993)'
_computing_data_collection       'DIFRAC (Gabe & White, 1993)'
_computing_data_reduction        'NRCVAX (Gabe et al.,  1989)'
_computing_molecular_graphics    'ORTEPIII (Burnett & Johnson, 1996)'
_computing_publication_material
'SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009)'
_computing_structure_refinement  'SHELXL97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      292(2)
_diffrn_measured_fraction_theta_full 0.996
_diffrn_measured_fraction_theta_max 0.996
_diffrn_measurement_device_type  'Enraf--Nonius CAD-4'
_diffrn_measurement_method       ω/2θ
_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  0.0106
_diffrn_reflns_av_sigmaI/netI    0.1039
_diffrn_reflns_limit_h_max       8
_diffrn_reflns_limit_h_min       -1
_diffrn_reflns_limit_k_max       20
_diffrn_reflns_limit_k_min       -2
_diffrn_reflns_limit_l_max       35
_diffrn_reflns_limit_l_min       -9
_diffrn_reflns_number            4699
_diffrn_reflns_theta_full        25.55
_diffrn_reflns_theta_max         25.55
_diffrn_reflns_theta_min         2.75
_diffrn_standards_decay_%        1.847
_diffrn_standards_interval_count 200
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    0.709
_exptl_absorpt_correction_T_max  0.7448
_exptl_absorpt_correction_T_min  0.7431
_exptl_absorpt_correction_type   sphere
_exptl_absorpt_process_details
'(modified interpolation procedure; Dwiggins, 1975)'
_exptl_crystal_colour            green
_exptl_crystal_density_diffrn    1.368
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             1592
_exptl_crystal_size_max          0.48
_exptl_crystal_size_mid          0.32
_exptl_crystal_size_min          0.30
_refine_diff_density_max         0.715
_refine_diff_density_min         -1.424
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.144
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     220
_refine_ls_number_reflns         3207
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.145
_refine_ls_R_factor_all          0.2068
_refine_ls_R_factor_gt           0.0791
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[σ²(Fo²)+(0.0948P)²] where P=(Fo²+2Fc²)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1783
_refine_ls_wR_factor_ref         0.2307
_reflns_number_gt                1518
_reflns_number_total             3207
_reflns_threshold_expression     I>2σ(I)
_cod_data_source_file            cv2549.cif
_cod_data_source_block           I
_cod_depositor_comments
;
The following automatic conversions were performed:
'_symmetry_cell_setting' value 'Orthorhombic' changed to 'orthorhombic'
according to '/home/saulius/struct/CIF-dictionaries/cif_core.dic'
dictionary named 'cif_core.dic' version 2.4.1 from 2010-06-29.

Automatic conversion script
Id: cif_fix_enum 1527 2010-12-29 10:47:43Z saulius 

The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Orthorhombic' changed to
'orthorhombic' according to
/home/saulius/struct/CIF-dictionaries/cif_core.dic dictionary named
'cif_core.dic' version 2.4.1 from 2010-06-29.

Automatic conversion script
Id: cif_fix_values 1715 2011-07-08 13:25:40Z adriana 
;
_cod_original_cell_volume        3703(2)
_cod_database_code               2221637
_cod_database_fobs_code          2221637
loop_
_symmetry_equiv_pos_as_xyz
'x, y, z'
'-x+1/2, y+1/2, z'
'x, -y+1/2, z+1/2'
'-x+1/2, -y, z+1/2'
'-x, -y, -z'
'x-1/2, -y-1/2, -z'
'-x, y-1/2, -z-1/2'
'x-1/2, y, -z-1/2'
loop_
_atom_site_type_symbol
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_U_iso_or_equiv
_atom_site_adp_type
_atom_site_calc_flag
_atom_site_refinement_flags
_atom_site_occupancy
_atom_site_disorder_assembly
_atom_site_disorder_group
Ni Ni1 0.0000 0.0000 0.0000 0.0340(4) Uani d S 1 . .
Cl Cl1 -0.2771(3) -0.07775(10) -0.01632(6) 0.0466(5) Uani d . 1 . .
N N1 -0.1100(8) 0.0385(3) 0.06038(16) 0.0359(13) Uani d . 1 . .
N N2 -0.2920(9) 0.0980(3) 0.10849(18) 0.0471(16) Uani d . 1 . .
N N3 -0.1313(8) 0.0963(3) -0.03282(17) 0.0408(14) Uani d U 1 . .
N N4 -0.3505(9) 0.1751(3) -0.05553(17) 0.0458(16) Uani d . 1 . .
C C1 -0.2707(11) 0.0710(4) 0.0662(2) 0.0459(18) Uani d . 1 . .
H H1 -0.3595 0.0749 0.0438 0.055 Uiso calc R 1 . .
C C2 -0.0234(12) 0.0452(5) 0.1010(2) 0.053(2) Uani d . 1 . .
H H2 0.0941 0.0271 0.1073 0.063 Uiso calc R 1 . .
C C3 -0.1335(12) 0.0818(5) 0.1306(2) 0.057(2) Uani d . 1 . .
H H3 -0.1062 0.0938 0.1604 0.068 Uiso calc R 1 . .
C C4 -0.4477(13) 0.1410(5) 0.1252(2) 0.062(3) Uani d . 1 . .
H H4A -0.5317 0.1503 0.1004 0.075 Uiso calc R 1 . .
H H4B -0.4061 0.1914 0.1360 0.075 Uiso calc R 1 . .
C C5 -0.5503(11) 0.1003(5) 0.1627(2) 0.048(2) Uani d . 1 . .
C C6 -0.6202(12) 0.1452(5) 0.1977(2) 0.058(2) Uani d . 1 . .
H H6 -0.5998 0.1988 0.1988 0.069 Uiso calc R 1 . .
C C7 -0.7196(15) 0.1086(8) 0.2304(3) 0.090(4) Uani d . 1 . .
H H7 -0.7623 0.1384 0.2545 0.107 Uiso calc R 1 . .
C C8 -0.7590(18) 0.0333(9) 0.2301(3) 0.102(4) Uani d . 1 . .
H H8 -0.8334 0.0117 0.2523 0.123 Uiso calc R 1 . .
C C9 -0.6870(18) -0.0131(6) 0.1959(4) 0.088(3) Uani d . 1 . .
H H9 -0.7085 -0.0666 0.1956 0.106 Uiso calc R 1 . .
C C10 -0.5826(14) 0.0214(5) 0.1620(3) 0.068(3) Uani d . 1 . .
H H10 -0.5346 -0.0091 0.1389 0.081 Uiso calc R 1 . .
C C11 -0.3010(12) 0.1020(4) -0.0462(2) 0.0489(19) Uani d U 1 . .
H H11 -0.3794 0.0594 -0.0489 0.059 Uiso calc R 1 . .
C C12 -0.0682(11) 0.1720(4) -0.0329(2) 0.0479(19) Uani d . 1 . .
H H12 0.0495 0.1871 -0.0246 0.057 Uiso calc R 1 . .
C C13 -0.2007(13) 0.2212(5) -0.0467(2) 0.057(2) Uani d . 1 . .
H H13 -0.1926 0.2752 -0.0496 0.068 Uiso calc R 1 . .
C C14 -0.5292(11) 0.2037(5) -0.0674(2) 0.059(2) Uani d . 1 . .
H H14A -0.5335 0.2594 -0.0614 0.071 Uiso calc R 1 . .
H H14B -0.6191 0.1789 -0.0480 0.071 Uiso calc R 1 . .
C C15 -0.5830(8) 0.1897(3) -0.11593(13) 0.051(2) Uani d G 1 . .
C C16 -0.4895(7) 0.2276(3) -0.15044(17) 0.069(2) Uani d G 1 . .
H H16 -0.3905 0.2597 -0.1437 0.083 Uiso calc R 1 . .
C C17 -0.5439(10) 0.2173(4) -0.19497(14) 0.091(4) Uani d G 1 . .
H H17 -0.4814 0.2426 -0.2181 0.109 Uiso calc R 1 . .
C C18 -0.6919(10) 0.1692(4) -0.20499(17) 0.106(4) Uani d G 1 . .
H H18 -0.7283 0.1623 -0.2348 0.127 Uiso calc R 1 . .
C C19 -0.7854(8) 0.1313(4) -0.1705(3) 0.102(4) Uani d G 1 . .
H H19 -0.8844 0.0991 -0.1772 0.122 Uiso calc R 1 . .
C C20 -0.7310(8) 0.1416(3) -0.1260(2) 0.071(3) Uani d G 1 . .
H H20 -0.7935 0.1163 -0.1029 0.086 Uiso calc R 1 . .
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'
Cl Cl 0.1484 0.1585 '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_site_symmetry_1
_geom_angle_site_symmetry_3
_geom_angle
_geom_angle_publ_flag
N1 Ni1 N1 5 . 180.0 ?
N1 Ni1 N3 5 . 91.4(2) ?
N1 Ni1 N3 . . 88.6(2) ?
N1 Ni1 N3 5 5 88.6(2) ?
N1 Ni1 N3 . 5 91.4(2) ?
N3 Ni1 N3 . 5 180.0 ?
N1 Ni1 Cl1 5 . 88.65(16) ?
N1 Ni1 Cl1 . . 91.35(16) ?
N3 Ni1 Cl1 . . 87.67(17) ?
N3 Ni1 Cl1 5 . 92.33(17) ?
N1 Ni1 Cl1 5 5 91.35(16) ?
N1 Ni1 Cl1 . 5 88.65(16) ?
N3 Ni1 Cl1 . 5 92.33(17) ?
N3 Ni1 Cl1 5 5 87.67(17) ?
Cl1 Ni1 Cl1 . 5 180.0 ?
C1 N1 C2 . . 105.2(6) ?
C1 N1 Ni1 . . 126.6(5) ?
C2 N1 Ni1 . . 127.6(5) ?
C1 N2 C3 . . 106.3(6) ?
C1 N2 C4 . . 125.9(7) ?
C3 N2 C4 . . 127.6(6) ?
C11 N3 C12 . . 104.3(6) ?
C11 N3 Ni1 . . 128.4(5) ?
C12 N3 Ni1 . . 125.2(5) ?
C11 N4 C13 . . 106.5(7) ?
C11 N4 C14 . . 128.1(7) ?
C13 N4 C14 . . 125.0(7) ?
N1 C1 N2 . . 111.9(6) ?
N1 C1 H1 . . 124.1 ?
N2 C1 H1 . . 124.1 ?
C3 C2 N1 . . 109.8(7) ?
C3 C2 H2 . . 125.1 ?
N1 C2 H2 . . 125.1 ?
C2 C3 N2 . . 106.8(6) ?
C2 C3 H3 . . 126.6 ?
N2 C3 H3 . . 126.6 ?
N2 C4 C5 . . 114.1(6) ?
N2 C4 H4A . . 108.7 ?
C5 C4 H4A . . 108.7 ?
N2 C4 H4B . . 108.7 ?
C5 C4 H4B . . 108.7 ?
H4A C4 H4B . . 107.6 ?
C10 C5 C6 . . 119.6(8) ?
C10 C5 C4 . . 121.8(7) ?
C6 C5 C4 . . 118.5(8) ?
C7 C6 C5 . . 118.2(9) ?
C7 C6 H6 . . 120.9 ?
C5 C6 H6 . . 120.9 ?
C8 C7 C6 . . 124.0(10) ?
C8 C7 H7 . . 118.0 ?
C6 C7 H7 . . 118.0 ?
C7 C8 C9 . . 118.7(10) ?
C7 C8 H8 . . 120.6 ?
C9 C8 H8 . . 120.6 ?
C8 C9 C10 . . 119.4(10) ?
C8 C9 H9 . . 120.3 ?
C10 C9 H9 . . 120.3 ?
C5 C10 C9 . . 120.0(9) ?
C5 C10 H10 . . 120.0 ?
C9 C10 H10 . . 120.0 ?
N3 C11 N4 . . 113.0(7) ?
N3 C11 H11 . . 123.5 ?
N4 C11 H11 . . 123.5 ?
C13 C12 N3 . . 110.4(8) ?
C13 C12 H12 . . 124.8 ?
N3 C12 H12 . . 124.8 ?
C12 C13 N4 . . 105.7(7) ?
C12 C13 H13 . . 127.1 ?
N4 C13 H13 . . 127.1 ?
N4 C14 C15 . . 114.5(6) ?
N4 C14 H14A . . 108.6 ?
C15 C14 H14A . . 108.6 ?
N4 C14 H14B . . 108.6 ?
C15 C14 H14B . . 108.6 ?
H14A C14 H14B . . 107.6 ?
C16 C15 C20 . . 120.0 ?
C16 C15 C14 . . 120.0(5) ?
C20 C15 C14 . . 119.9(5) ?
C17 C16 C15 . . 120.0 ?
C17 C16 H16 . . 120.0 ?
C15 C16 H16 . . 120.0 ?
C18 C17 C16 . . 120.0 ?
C18 C17 H17 . . 120.0 ?
C16 C17 H17 . . 120.0 ?
C17 C18 C19 . . 120.0 ?
C17 C18 H18 . . 120.0 ?
C19 C18 H18 . . 120.0 ?
C20 C19 C18 . . 120.0 ?
C20 C19 H19 . . 120.0 ?
C18 C19 H19 . . 120.0 ?
C19 C20 C15 . . 120.0 ?
C19 C20 H20 . . 120.0 ?
C15 C20 H20 . . 120.0 ?
loop_
_geom_bond_atom_site_label_1
_geom_bond_atom_site_label_2
_geom_bond_site_symmetry_2
_geom_bond_distance
_geom_bond_publ_flag
Ni1 N1 5 2.070(5) ?
Ni1 N1 . 2.070(5) ?
Ni1 N3 . 2.140(6) ?
Ni1 N3 5 2.140(6) ?
Ni1 Cl1 . 2.468(2) ?
Ni1 Cl1 5 2.468(2) ?
N1 C1 . 1.310(9) ?
N1 C2 . 1.365(8) ?
N2 C1 . 1.345(8) ?
N2 C3 . 1.358(10) ?
N2 C4 . 1.441(9) ?
N3 C11 . 1.304(9) ?
N3 C12 . 1.376(8) ?
N4 C11 . 1.333(8) ?
N4 C13 . 1.373(10) ?
N4 C14 . 1.436(9) ?
C1 H1 . 0.9300 ?
C2 C3 . 1.345(10) ?
C2 H2 . 0.9300 ?
C3 H3 . 0.9300 ?
C4 C5 . 1.510(10) ?
C4 H4A . 0.9700 ?
C4 H4B . 0.9700 ?
C5 C10 . 1.371(10) ?
C5 C6 . 1.389(9) ?
C6 C7 . 1.365(13) ?
C6 H6 . 0.9300 ?
C7 C8 . 1.320(15) ?
C7 H7 . 0.9300 ?
C8 C9 . 1.391(15) ?
C8 H8 . 0.9300 ?
C9 C10 . 1.392(13) ?
C9 H9 . 0.9300 ?
C10 H10 . 0.9300 ?
C11 H11 . 0.9300 ?
C12 C13 . 1.345(11) ?
C12 H12 . 0.9300 ?
C13 H13 . 0.9300 ?
C14 C15 . 1.512(8) ?
C14 H14A . 0.9700 ?
C14 H14B . 0.9700 ?
C15 C16 . 1.3900 ?
C15 C20 . 1.3900 ?
C16 C17 . 1.3900 ?
C16 H16 . 0.9300 ?
C17 C18 . 1.3900 ?
C17 H17 . 0.9300 ?
C18 C19 . 1.3900 ?
C18 H18 . 0.9300 ?
C19 C20 . 1.3900 ?
C19 H19 . 0.9300 ?
C20 H20 . 0.9300 ?
loop_
_geom_hbond_atom_site_label_D
_geom_hbond_atom_site_label_H
_geom_hbond_atom_site_label_A
_geom_hbond_site_symmetry_A
_geom_hbond_distance_DH
_geom_hbond_distance_HA
_geom_hbond_distance_DA
_geom_hbond_angle_DHA
C1 H1 Cl1 5_455 0.93 2.77 3.617(8) 151
C14 H14B Cl1 5_455 0.97 2.68 3.579(8) 153
C13 H13 Cl1 2_455 0.93 2.71 3.561(9) 152
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_site_symmetry_1
_geom_torsion_site_symmetry_2
_geom_torsion_site_symmetry_3
_geom_torsion_site_symmetry_4
_geom_torsion
_geom_torsion_publ_flag
N1 Ni1 N1 C1 5 . . . -16E1(2) ?
N3 Ni1 N1 C1 . . . . 35.5(6) ?
N3 Ni1 N1 C1 5 . . . -144.5(6) ?
Cl1 Ni1 N1 C1 . . . . -52.1(6) ?
Cl1 Ni1 N1 C1 5 . . . 127.9(6) ?
N1 Ni1 N1 C2 5 . . . 3E1(2) ?
N3 Ni1 N1 C2 . . . . -135.0(6) ?
N3 Ni1 N1 C2 5 . . . 45.0(6) ?
Cl1 Ni1 N1 C2 . . . . 137.4(6) ?
Cl1 Ni1 N1 C2 5 . . . -42.6(6) ?
N1 Ni1 N3 C11 5 . . . 98.3(6) ?
N1 Ni1 N3 C11 . . . . -81.7(6) ?
N3 Ni1 N3 C11 5 . . . -8E1(6) ?
Cl1 Ni1 N3 C11 . . . . 9.8(6) ?
Cl1 Ni1 N3 C11 5 . . . -170.2(6) ?
N1 Ni1 N3 C12 5 . . . -100.9(5) ?
N1 Ni1 N3 C12 . . . . 79.1(5) ?
N3 Ni1 N3 C12 5 . . . 8E1(6) ?
Cl1 Ni1 N3 C12 . . . . 170.5(5) ?
Cl1 Ni1 N3 C12 5 . . . -9.5(5) ?
C2 N1 C1 N2 . . . . -0.2(8) ?
Ni1 N1 C1 N2 . . . . -172.4(4) ?
C3 N2 C1 N1 . . . . 0.4(8) ?
C4 N2 C1 N1 . . . . 176.0(7) ?
C1 N1 C2 C3 . . . . -0.2(9) ?
Ni1 N1 C2 C3 . . . . 171.9(5) ?
N1 C2 C3 N2 . . . . 0.4(10) ?
C1 N2 C3 C2 . . . . -0.5(9) ?
C4 N2 C3 C2 . . . . -176.0(7) ?
C1 N2 C4 C5 . . . . 117.9(8) ?
C3 N2 C4 C5 . . . . -67.5(12) ?
N2 C4 C5 C10 . . . . -40.6(12) ?
N2 C4 C5 C6 . . . . 142.2(8) ?
C10 C5 C6 C7 . . . . -0.1(12) ?
C4 C5 C6 C7 . . . . 177.2(8) ?
C5 C6 C7 C8 . . . . -2.4(15) ?
C6 C7 C8 C9 . . . . 3.8(18) ?
C7 C8 C9 C10 . . . . -2.7(18) ?
C6 C5 C10 C9 . . . . 0.9(13) ?
C4 C5 C10 C9 . . . . -176.2(9) ?
C8 C9 C10 C5 . . . . 0.4(16) ?
C12 N3 C11 N4 . . . . 1.1(7) ?
Ni1 N3 C11 N4 . . . . 165.0(4) ?
C13 N4 C11 N3 . . . . -1.2(8) ?
C14 N4 C11 N3 . . . . -174.3(6) ?
C11 N3 C12 C13 . . . . -0.6(8) ?
Ni1 N3 C12 C13 . . . . -165.1(5) ?
N3 C12 C13 N4 . . . . -0.1(8) ?
C11 N4 C13 C12 . . . . 0.8(8) ?
C14 N4 C13 C12 . . . . 174.2(6) ?
C11 N4 C14 C15 . . . . -79.1(9) ?
C13 N4 C14 C15 . . . . 109.0(8) ?
N4 C14 C15 C16 . . . . -66.5(8) ?
N4 C14 C15 C20 . . . . 116.2(7) ?
C20 C15 C16 C17 . . . . 0.0 ?
C14 C15 C16 C17 . . . . -177.2(5) ?
C15 C16 C17 C18 . . . . 0.0 ?
C16 C17 C18 C19 . . . . 0.0 ?
C17 C18 C19 C20 . . . . 0.0 ?
C18 C19 C20 C15 . . . . 0.0 ?
C16 C15 C20 C19 . . . . 0.0 ?
C14 C15 C20 C19 . . . . 177.2(5) ?
