Towards novel C-N materials: Crystal structures of two polymorphs of guanidinium dicyanamide and their thermal conversion into melamine.
Wolfgang Schnick; Bettina V. Lotsch; New J.Chem.(Nouv.J.Chim.)  (2004) –; doi:

data_7050336
_publ_section_title
;
Towards novel C-N materials: Crystal structures of
two polymorphs of guanidinium dicyanamide and their thermal conversion
into melamine.
;
_journal_name_full               'New J.Chem.(Nouv.J.Chim.)'
_journal_year                    2004
_chemical_formula_moiety         '[CN3H6][N(CN)2]'
_chemical_formula_sum            'C3 H6 N6'
_chemical_formula_weight         126.14
_chemical_melting_point          333
_chemical_name_common            'beta-Guanidinium dicyanamide'
_chemical_name_systematic
;
beta-Guanidinium dicyanamide
;
_space_group_IT_number           33
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  'P 2c -2n'
_symmetry_space_group_name_H-M   'P n a 21'
_atom_sites_solution_hydrogens   difmap
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            8
_cell_length_a                   13.731(3)
_cell_length_b                   4.9553(10)
_cell_length_c                   18.029(4)
_cell_measurement_reflns_used    6856
_cell_measurement_temperature    200
_cell_measurement_theta_max      27.485
_cell_measurement_theta_min      3.134
_cell_volume                     1226.7(4)
_diffrn_ambient_temperature      200
_diffrn_detector_area_resol_mean 9
_diffrn_measurement_device
;                                 '95mm CCD camera on'
'\k-goniostat'
;
_diffrn_measurement_device_type  KappaCCD
_diffrn_measurement_method       omega-scan
_diffrn_radiation_monochromator
;                                 'vertically mounted'
'graphite crystal'
;
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0499
_diffrn_reflns_av_sigmaI/netI    0.0406
_diffrn_reflns_limit_h_max       17
_diffrn_reflns_limit_h_min       -17
_diffrn_reflns_limit_k_max       6
_diffrn_reflns_limit_k_min       -6
_diffrn_reflns_limit_l_max       23
_diffrn_reflns_limit_l_min       -17
_diffrn_reflns_number            16123
_diffrn_reflns_theta_max         27.47
_diffrn_reflns_theta_min         3.18
_diffrn_standards_decay_%        ?
_diffrn_standards_interval_count ?
_diffrn_standards_interval_time  ?
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.102
_exptl_absorpt_correction_T_max  ?
_exptl_absorpt_correction_T_min  ?
_exptl_absorpt_correction_type   none
_exptl_absorpt_process_details   ?
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.366
_exptl_crystal_density_meas      ?
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             528
_exptl_crystal_size_max          0.30
_exptl_crystal_size_mid          0.22
_exptl_crystal_size_min          0.09
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   -2(3)
_refine_ls_extinction_coef       0.013(2)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_ref   1.043
_refine_ls_hydrogen_treatment    refall
_refine_ls_matrix_type           full
_refine_ls_number_parameters     212
_refine_ls_number_reflns         2510
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.043
_refine_ls_R_factor_all          0.0687
_refine_ls_R_factor_gt           0.0423
_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/[\s^2^(Fo^2^)+(0.0569P)^2^+0.1346P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0967
_refine_ls_wR_factor_ref         0.1100
_reflns_number_gt                1838
_reflns_number_total             2510
_reflns_threshold_expression     >2sigma(I)
_cod_database_code               7050336