# Supplementary Material (ESI) for Perkin Transactions
# This journal is © The Royal Society of Chemistry 2002

data_akd8 

_database_code_CSD	183160


_journal_coden_Cambridge      188

loop_
_publ_author_name
'Das, Amit Kumar'
'Bertolasi, V.'
'Kundu, Sandip K.'
'Mazumdar, Pooja A.'
'Pramanik, Animesh'

_publ_contact_author_name 'Dr. Amit Kumar Das'  
_publ_contact_author_address 
; 
Department of Biotechnology
Indian Institute of Technology
Kharagpur 721302
India
;
_publ_contact_author_phone     '0091 3222 83756' 
_publ_contact_author_fax       '0091 3222 55303' 
_publ_contact_author_email     'amitk@hijli.iitkgp.ernet.in' 
_publ_requested_journal        'Perkin Transactions 2'

_publ_section_title
;
Parallel b-sheet assemblage in a model dipeptide: 
An X-ray diffraction study
; 

_audit_creation_method            SHELXL-97 
_chemical_name_systematic 
; 
? 
; 
_chemical_name_common             ? 
_chemical_melting_point           ? 
_chemical_formula_moiety          ? 
_chemical_formula_sum 
'C16 H22 N2 O5' 
_chemical_formula_weight          322.36 

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' 
'O'  'O'   0.0106   0.0060 
'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4' 

_symmetry_cell_setting            'Monoclinic '
_symmetry_space_group_name_H-M    'P 21' 

loop_ 
_symmetry_equiv_pos_as_xyz 
'x, y, z' 
'-x, y+1/2, -z' 

_cell_length_a                    5.0920(2) 
_cell_length_b                    28.9279(9) 
_cell_length_c                    5.7024(2) 
_cell_angle_alpha                 90.00 
_cell_angle_beta                  90.021(2) 
_cell_angle_gamma                 90.00 
_cell_volume                      839.97(5) 
_cell_formula_units_Z             2 
_cell_measurement_temperature     294(2) 
_cell_measurement_reflns_used     3553
_cell_measurement_theta_min       0 
_cell_measurement_theta_max       28

_exptl_crystal_description        prism 
_exptl_crystal_colour             ? 
_exptl_crystal_size_max           0.35 
_exptl_crystal_size_mid           0.20 
_exptl_crystal_size_min           0.18
_exptl_crystal_density_meas       ? 
_exptl_crystal_density_diffrn     1.275 
_exptl_crystal_density_method     'not measured' 
_exptl_crystal_F_000              344 
_exptl_absorpt_coefficient_mu     0.095 
_exptl_absorpt_correction_type    none 
_exptl_absorpt_correction_T_min   ? 
_exptl_absorpt_correction_T_max   ? 
_exptl_absorpt_process_details    ? 

_exptl_special_details 
; 
? 
; 

_diffrn_ambient_temperature       294(2) 
_diffrn_radiation_wavelength      0.71069 
_diffrn_radiation_type            MoK\a 
_diffrn_radiation_source          'fine-focus sealed tube' 
_diffrn_radiation_monochromator   graphite 
_diffrn_measurement_device_type   'Nonius Kappa CCD'
_diffrn_measurement_method        '\f scans and \w scans' 
_diffrn_detector_area_resol_mean  ? 
_diffrn_reflns_number             3553 
_diffrn_reflns_av_R_equivalents   0.0211 
_diffrn_reflns_av_sigmaI/netI     0.0343 
_diffrn_reflns_limit_h_min        -6 
_diffrn_reflns_limit_h_max        6 
_diffrn_reflns_limit_k_min        -35 
_diffrn_reflns_limit_k_max        37 
_diffrn_reflns_limit_l_min        -6 
_diffrn_reflns_limit_l_max        7 
_diffrn_reflns_theta_min          3.57 
_diffrn_reflns_theta_max          27.50 
_reflns_number_total              2679 
_reflns_number_gt                 2431 
_reflns_threshold_expression      >2sigma(I) 

_computing_data_collection        'Kappa CCD server software (Nonius, 1997)' 
_computing_cell_refinement        'Denzo-SMN (Otwinowski & Minor, 1997)' 
_computing_data_reduction         'Denzo-SMN (Otwinowski & Minor, 1997)' 
_computing_structure_solution     'SHELXS-97 (Sheldrick, 1990)' 
_computing_structure_refinement   'SHELXL-97 (Sheldrick, 1997)' 
_computing_molecular_graphics     'PLATON (Spek,1990)'
_computing_publication_material   ? 

_refine_special_details 
; 
Refinement of F^2^ against ALL reflections.  The weighted R-factor wR and 
goodness of fit S are based on F^2^, conventional R-factors R are based 
on F, with F set to zero for negative F^2^. The threshold expression of 
F^2^ > 2sigma(F^2^) is used only for calculating R-factors(gt) etc. and is 
not relevant to the choice of reflections for refinement.  R-factors based 
on F^2^ are statistically about twice as large as those based on F, and R- 
factors based on ALL data will be even larger. 
; 

_refine_ls_structure_factor_coef  Fsqd  
_refine_ls_matrix_type            full 
_refine_ls_weighting_scheme       calc  
_refine_ls_weighting_details 
'calc w=1/[\s^2^(Fo^2^)+(0.0531P)^2^+0.0618P] where P=(Fo^2^+2Fc^2^)/3' 
_atom_sites_solution_primary      direct 
_atom_sites_solution_secondary    difmap 
_atom_sites_solution_hydrogens    geom 
_refine_ls_hydrogen_treatment     mixed 
_refine_ls_extinction_method      none 
_refine_ls_extinction_coef        ? 
_refine_ls_abs_structure_details 
'Flack H D (1983), Acta Cryst. A39, 876-881' 
_refine_ls_abs_structure_Flack    -0.8(9) 
_refine_ls_number_reflns          2679 
_refine_ls_number_parameters      263 
_refine_ls_number_restraints      1 
_refine_ls_R_factor_all           0.0376 
_refine_ls_R_factor_gt            0.0333 
_refine_ls_wR_factor_ref          0.0905 
_refine_ls_wR_factor_gt           0.0872 
_refine_ls_goodness_of_fit_ref    1.015 
_refine_ls_restrained_S_all       1.014 
_refine_ls_shift/su_max           0.000 
_refine_ls_shift/su_mean          0.000 

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 
C1 C 1.2119(6) 0.57991(9) 0.6054(6) 0.0858(8) Uani 1 1 d . . . 
H1A H 1.1319 0.6090 0.6428 0.129 Uiso 1 1 calc R . . 
H1B H 1.2522 0.5789 0.4411 0.129 Uiso 1 1 calc R . . 
H1C H 1.3707 0.5764 0.6945 0.129 Uiso 1 1 calc R . . 
O2 O 1.0330(4) 0.54288(6) 0.6624(3) 0.0724(5) Uani 1 1 d . . . 
C3 C 0.9070(5) 0.54521(7) 0.8654(4) 0.0606(5) Uani 1 1 d . . . 
O4 O 0.9392(4) 0.57615(7) 1.0038(4) 0.0971(7) Uani 1 1 d . . . 
C5 C 0.7220(4) 0.50613(7) 0.9000(3) 0.0529(5) Uani 1 1 d . . . 
C6 C 0.5594(6) 0.50620(10) 1.0951(4) 0.0698(6) Uani 1 1 d . . . 
C7 C 0.3762(5) 0.47163(10) 1.1238(4) 0.0717(7) Uani 1 1 d . . . 
C8 C 0.3578(4) 0.43615(9) 0.9630(4) 0.0594(5) Uani 1 1 d . . . 
C9 C 0.5256(3) 0.43496(6) 0.7706(3) 0.0446(4) Uani 1 1 d . . . 
C10 C 0.7051(4) 0.47048(6) 0.7377(3) 0.0456(4) Uani 1 1 d . . . 
N11 N 0.5057(3) 0.39780(5) 0.6090(3) 0.0446(3) Uani 1 1 d . . . 
C12 C 0.7107(3) 0.37745(6) 0.5003(3) 0.0414(4) Uani 1 1 d . . . 
O13 O 0.9386(2) 0.38971(5) 0.5252(3) 0.0626(4) Uani 1 1 d . . . 
C14 C 0.6398(4) 0.33586(6) 0.3468(3) 0.0420(4) Uani 1 1 d . . . 
C15 C 0.8057(5) 0.33486(9) 0.1255(3) 0.0546(5) Uani 1 1 d . . . 
N16 N 0.6804(3) 0.29394(5) 0.4829(3) 0.0435(3) Uani 1 1 d . . . 
C17 C 0.4813(3) 0.27093(5) 0.5811(3) 0.0388(3) Uani 1 1 d . . . 
O18 O 0.2518(2) 0.28115(5) 0.5569(3) 0.0563(4) Uani 1 1 d . . . 
O19 O 0.5713(2) 0.23510(5) 0.7069(3) 0.0523(4) Uani 1 1 d . . . 
C20 C 0.3865(3) 0.20254(7) 0.8210(3) 0.0484(4) Uani 1 1 d . . . 
C21 C 0.2143(5) 0.22791(10) 0.9927(4) 0.0664(6) Uani 1 1 d . . . 
H21A H 0.3200 0.2484 1.0858 0.100 Uiso 1 1 calc R . . 
H21B H 0.1281 0.2060 1.0931 0.100 Uiso 1 1 calc R . . 
H21C H 0.0850 0.2455 0.9087 0.100 Uiso 1 1 calc R . . 
C22 C 0.2322(6) 0.17703(9) 0.6365(4) 0.0664(6) Uani 1 1 d . . . 
C23 C 0.5671(5) 0.16986(10) 0.9516(7) 0.0915(10) Uani 1 1 d . . . 
H23A H 0.6848 0.1554 0.8426 0.137 Uiso 1 1 calc R . . 
H23B H 0.4644 0.1466 1.0294 0.137 Uiso 1 1 calc R . . 
H23C H 0.6666 0.1869 1.0656 0.137 Uiso 1 1 calc R . . 
H4 H 0.567(5) 0.5302(10) 1.198(4) 0.069(7) Uiso 1 1 d . . . 
H5 H 0.261(7) 0.4694(11) 1.264(6) 0.094(9) Uiso 1 1 d . . . 
H6 H 0.233(5) 0.4114(9) 0.979(3) 0.055(6) Uiso 1 1 d . . . 
H7 H 0.821(4) 0.4707(7) 0.601(4) 0.046(5) Uiso 1 1 d . . . 
H8 H 0.339(5) 0.3851(10) 0.586(4) 0.070(7) Uiso 1 1 d . . . 
H9 H 0.449(4) 0.3379(7) 0.309(3) 0.037(4) Uiso 1 1 d . . . 
H10 H 0.781(6) 0.3627(11) 0.041(5) 0.078(8) Uiso 1 1 d . . . 
H11 H 0.748(5) 0.3076(10) 0.028(4) 0.071(7) Uiso 1 1 d . . . 
H12 H 0.996(5) 0.3321(9) 0.172(4) 0.061(6) Uiso 1 1 d . . . 
H13 H 0.831(4) 0.2864(8) 0.511(3) 0.046(5) Uiso 1 1 d . . . 
H17 H 0.137(6) 0.1488(11) 0.711(5) 0.084(8) Uiso 1 1 d . . . 
H18 H 0.367(5) 0.1615(10) 0.515(4) 0.077(7) Uiso 1 1 d . . . 
H19 H 0.093(7) 0.1967(13) 0.556(6) 0.102(10) Uiso 1 1 d . . . 

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 
C1 0.090(2) 0.0511(13) 0.117(2) -0.0001(13) -0.0044(17) -0.0169(13) 
O2 0.0885(12) 0.0498(8) 0.0789(10) -0.0114(8) 0.0011(9) -0.0191(8) 
C3 0.0618(13) 0.0435(10) 0.0764(13) -0.0154(10) -0.0124(11) 0.0100(9) 
O4 0.1110(16) 0.0654(12) 0.1149(14) -0.0464(11) 0.0035(12) -0.0061(11) 
C5 0.0533(11) 0.0476(10) 0.0577(10) -0.0066(8) -0.0071(9) 0.0132(9) 
C6 0.0780(16) 0.0723(15) 0.0592(12) -0.0142(12) 0.0006(11) 0.0209(13) 
C7 0.0685(16) 0.0870(17) 0.0596(12) 0.0016(12) 0.0138(11) 0.0233(14) 
C8 0.0463(11) 0.0662(13) 0.0657(12) 0.0100(11) 0.0086(9) 0.0097(10) 
C9 0.0348(9) 0.0460(10) 0.0531(9) 0.0044(8) -0.0036(7) 0.0066(7) 
C10 0.0418(10) 0.0442(9) 0.0508(9) -0.0015(7) -0.0013(8) 0.0053(8) 
N11 0.0300(7) 0.0433(8) 0.0604(8) 0.0029(7) -0.0036(6) -0.0030(6) 
C12 0.0308(8) 0.0323(7) 0.0612(9) 0.0046(7) -0.0088(7) -0.0025(6) 
O13 0.0283(6) 0.0505(8) 0.1090(11) -0.0234(8) -0.0055(7) -0.0032(5) 
C14 0.0349(9) 0.0325(7) 0.0585(9) 0.0072(8) -0.0120(7) -0.0033(7) 
C15 0.0603(13) 0.0518(10) 0.0518(10) 0.0068(10) -0.0071(9) -0.0009(11) 
N16 0.0279(7) 0.0350(7) 0.0675(9) 0.0110(6) -0.0083(7) -0.0006(6) 
C17 0.0331(8) 0.0335(8) 0.0496(8) 0.0007(6) -0.0047(7) 0.0000(6) 
O18 0.0290(6) 0.0611(9) 0.0788(8) 0.0172(7) -0.0038(6) 0.0039(6) 
O19 0.0307(7) 0.0462(7) 0.0799(9) 0.0234(6) 0.0005(6) -0.0015(5) 
C20 0.0364(9) 0.0479(10) 0.0609(10) 0.0136(8) 0.0023(8) -0.0066(8) 
C21 0.0622(14) 0.0805(16) 0.0566(10) -0.0023(11) 0.0044(10) -0.0084(12) 
C22 0.0778(16) 0.0544(13) 0.0671(13) -0.0041(10) 0.0134(12) -0.0222(12) 
C23 0.0523(14) 0.0823(18) 0.140(2) 0.0657(18) 0.0028(14) -0.0021(12) 

_geom_special_details 
; 
All esds (except the esd in the dihedral angle between two l.s. planes) 
are estimated using the full covariance matrix.  The cell esds are taken 
into account individually in the estimation of esds in distances, angles 
and torsion angles; correlations between esds in cell parameters are only 
used when they are defined by crystal symmetry.  An approximate (isotropic) 
treatment of cell esds is used for estimating esds involving l.s. planes. 
; 

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 
C1 O2 1.443(3) . ? 
C1 H1A 0.9600 . ? 
C1 H1B 0.9600 . ? 
C1 H1C 0.9600 . ? 
O2 C3 1.326(3) . ? 
C3 O4 1.205(3) . ? 
C3 C5 1.485(3) . ? 
C5 C6 1.387(3) . ? 
C5 C10 1.388(3) . ? 
C6 C7 1.377(4) . ? 
C6 H4 0.91(3) . ? 
C7 C8 1.380(4) . ? 
C7 H5 0.99(3) . ? 
C8 C9 1.391(3) . ? 
C8 H6 0.96(3) . ? 
C9 C10 1.388(3) . ? 
C9 N11 1.419(2) . ? 
C10 H7 0.98(2) . ? 
N11 C12 1.349(2) . ? 
N11 H8 0.93(3) . ? 
C12 O13 1.222(2) . ? 
C12 C14 1.531(2) . ? 
C14 N16 1.454(2) . ? 
C14 C15 1.519(3) . ? 
C14 H9 1.00(2) . ? 
C15 H10 0.95(3) . ? 
C15 H11 1.01(3) . ? 
C15 H12 1.01(3) . ? 
N16 C17 1.336(2) . ? 
N16 H13 0.81(2) . ? 
C17 O18 1.214(2) . ? 
C17 O19 1.341(2) . ? 
O19 C20 1.482(2) . ? 
C20 C21 1.506(3) . ? 
C20 C22 1.506(3) . ? 
C20 C23 1.514(3) . ? 
C21 H21A 0.9600 . ? 
C21 H21B 0.9600 . ? 
C21 H21C 0.9600 . ? 
C22 H17 1.04(3) . ? 
C22 H18 1.07(3) . ? 
C22 H19 1.02(4) . ? 
C23 H23A 0.9600 . ? 
C23 H23B 0.9600 . ? 
C23 H23C 0.9600 . ? 

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 
O2 C1 H1A 109.5 . . ? 
O2 C1 H1B 109.5 . . ? 
H1A C1 H1B 109.5 . . ? 
O2 C1 H1C 109.5 . . ? 
H1A C1 H1C 109.5 . . ? 
H1B C1 H1C 109.5 . . ? 
C3 O2 C1 117.7(2) . . ? 
O4 C3 O2 123.0(2) . . ? 
O4 C3 C5 124.4(2) . . ? 
O2 C3 C5 112.62(17) . . ? 
C6 C5 C10 119.9(2) . . ? 
C6 C5 C3 119.0(2) . . ? 
C10 C5 C3 121.07(18) . . ? 
C7 C6 C5 119.9(2) . . ? 
C7 C6 H4 120.5(16) . . ? 
C5 C6 H4 119.4(16) . . ? 
C6 C7 C8 120.5(2) . . ? 
C6 C7 H5 122.9(19) . . ? 
C8 C7 H5 116.5(19) . . ? 
C7 C8 C9 120.1(2) . . ? 
C7 C8 H6 122.5(13) . . ? 
C9 C8 H6 117.4(13) . . ? 
C10 C9 C8 119.53(19) . . ? 
C10 C9 N11 121.30(15) . . ? 
C8 C9 N11 119.16(19) . . ? 
C9 C10 C5 120.01(17) . . ? 
C9 C10 H7 120.6(13) . . ? 
C5 C10 H7 119.4(13) . . ? 
C12 N11 C9 125.02(15) . . ? 
C12 N11 H8 118.0(16) . . ? 
C9 N11 H8 116.8(16) . . ? 
O13 C12 N11 123.69(17) . . ? 
O13 C12 C14 121.22(16) . . ? 
N11 C12 C14 115.05(15) . . ? 
N16 C14 C15 110.40(16) . . ? 
N16 C14 C12 108.48(13) . . ? 
C15 C14 C12 111.04(16) . . ? 
N16 C14 H9 107.6(12) . . ? 
C15 C14 H9 111.2(10) . . ? 
C12 C14 H9 108.0(11) . . ? 
C14 C15 H10 109.4(16) . . ? 
C14 C15 H11 108.2(14) . . ? 
H10 C15 H11 110(2) . . ? 
C14 C15 H12 108.6(12) . . ? 
H10 C15 H12 109(2) . . ? 
H11 C15 H12 111(2) . . ? 
C17 N16 C14 122.12(15) . . ? 
C17 N16 H13 120.0(14) . . ? 
C14 N16 H13 117.5(15) . . ? 
O18 C17 N16 124.17(16) . . ? 
O18 C17 O19 125.34(16) . . ? 
N16 C17 O19 110.49(14) . . ? 
C17 O19 C20 120.60(13) . . ? 
O19 C20 C21 110.23(17) . . ? 
O19 C20 C22 109.63(16) . . ? 
C21 C20 C22 112.90(18) . . ? 
O19 C20 C23 103.14(15) . . ? 
C21 C20 C23 109.8(2) . . ? 
C22 C20 C23 110.7(2) . . ? 
C20 C21 H21A 109.5 . . ? 
C20 C21 H21B 109.5 . . ? 
H21A C21 H21B 109.5 . . ? 
C20 C21 H21C 109.5 . . ? 
H21A C21 H21C 109.5 . . ? 
H21B C21 H21C 109.5 . . ? 
C20 C22 H17 110.1(15) . . ? 
C20 C22 H18 108.8(14) . . ? 
H17 C22 H18 103(2) . . ? 
C20 C22 H19 113.8(19) . . ? 
H17 C22 H19 107(2) . . ? 
H18 C22 H19 113(2) . . ? 
C20 C23 H23A 109.5 . . ? 
C20 C23 H23B 109.5 . . ? 
H23A C23 H23B 109.5 . . ? 
C20 C23 H23C 109.5 . . ? 
H23A C23 H23C 109.5 . . ? 
H23B C23 H23C 109.5 . . ? 

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 
C1 O2 C3 O4 -1.4(4) . . . . ? 
C1 O2 C3 C5 177.9(2) . . . . ? 
O4 C3 C5 C6 5.0(3) . . . . ? 
O2 C3 C5 C6 -174.3(2) . . . . ? 
O4 C3 C5 C10 -176.7(2) . . . . ? 
O2 C3 C5 C10 4.0(3) . . . . ? 
C10 C5 C6 C7 -1.9(3) . . . . ? 
C3 C5 C6 C7 176.4(2) . . . . ? 
C5 C6 C7 C8 1.8(4) . . . . ? 
C6 C7 C8 C9 0.3(3) . . . . ? 
C7 C8 C9 C10 -2.1(3) . . . . ? 
C7 C8 C9 N11 179.1(2) . . . . ? 
C8 C9 C10 C5 2.0(3) . . . . ? 
N11 C9 C10 C5 -179.33(16) . . . . ? 
C6 C5 C10 C9 0.0(3) . . . . ? 
C3 C5 C10 C9 -178.23(18) . . . . ? 
C10 C9 N11 C12 38.6(3) . . . . ? 
C8 C9 N11 C12 -142.70(19) . . . . ? 
C9 N11 C12 O13 -1.8(3) . . . . ? 
C9 N11 C12 C14 175.94(15) . . . . ? 
O13 C12 C14 N16 81.6(2) . . . . ? 
N11 C12 C14 N16 -96.28(18) . . . . ? 
O13 C12 C14 C15 -39.9(2) . . . . ? 
N11 C12 C14 C15 142.23(16) . . . . ? 
C15 C14 N16 C17 -136.48(18) . . . . ? 
C12 C14 N16 C17 101.64(19) . . . . ? 
C14 N16 C17 O18 3.9(3) . . . . ? 
C14 N16 C17 O19 -176.68(15) . . . . ? 
O18 C17 O19 C20 3.2(3) . . . . ? 
N16 C17 O19 C20 -176.21(16) . . . . ? 
C17 O19 C20 C21 -60.0(2) . . . . ? 
C17 O19 C20 C22 64.9(2) . . . . ? 
C17 O19 C20 C23 -177.1(2) . . . . ? 

_diffrn_measured_fraction_theta_max    0.922 
_diffrn_reflns_theta_full              27.50 
_diffrn_measured_fraction_theta_full   0.922 
_refine_diff_density_max    0.098 
_refine_diff_density_min   -0.119 
_refine_diff_density_rms    0.026