Crystal Structures of Two Polymorphs of Ca3[Al2N4]
M. Ludwig; J. Jäger; R. Niewa; R. Kniep; Inorganic Chemistry 39 (2000) 5909–5911; doi:10.1021/ic0002869

data_4321677
_publ_section_title
;
 Crystal Structures of Two Polymorphs of Ca3[Al2N4]
;
_journal_name_full               'Inorganic Chemistry'
_journal_page_first              5909
_journal_page_last               5911
_journal_paper_doi               10.1021/ic0002869
_journal_volume                  39
_journal_year                    2000
_chemical_formula_sum            'Al2 Ca3 N4'
_chemical_formula_weight         230.24
_chemical_name_common            'alpha-Tricalcium nitrido dialuminate'
_chemical_name_systematic
;
  ?
;
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2ybc'
_symmetry_space_group_name_H-M   'P 1 21/c 1'
_atom_sites_solution_hydrogens   none
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 111.62(3)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   9.572(3)
_cell_length_b                   5.802(3)
_cell_length_c                   9.563(5)
_cell_measurement_reflns_used    25
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      16
_cell_measurement_theta_min      10
_cell_volume                     493.7(4)
_computing_molecular_graphics    Diamond
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.897
_diffrn_measured_fraction_theta_max 0.897
_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  0.0235
_diffrn_reflns_av_sigmaI/netI    0.0190
_diffrn_reflns_limit_h_max       12
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       1
_diffrn_reflns_limit_k_min       -8
_diffrn_reflns_limit_l_max       12
_diffrn_reflns_limit_l_min       -1
_diffrn_reflns_number            5144
_diffrn_reflns_theta_full        30.00
_diffrn_reflns_theta_max         30.00
_diffrn_reflns_theta_min         2.29
_diffrn_standards_decay_%        0
_diffrn_standards_interval_count 100
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    3.570
_exptl_absorpt_correction_type   difabs
_exptl_crystal_colour            green
_exptl_crystal_density_diffrn    3.097
_exptl_crystal_density_method    'not measured'
_exptl_crystal_F_000             456
_refine_diff_density_max         1.380
_refine_diff_density_min         -1.381
_refine_diff_density_rms         0.335
_refine_ls_extinction_coef       0.017(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   1.418
_refine_ls_hydrogen_treatment    none
_refine_ls_matrix_type           full
_refine_ls_number_parameters     83
_refine_ls_number_reflns         1295
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.418
_refine_ls_R_factor_all          0.0841
_refine_ls_R_factor_gt           0.0835
_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^)+(0.0000P)^2^+22.3100P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.2048
_refine_ls_wR_factor_ref         0.2050
_reflns_number_gt                1276
_reflns_number_total             1295
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ic0002869_1.cif
_cod_data_source_block           alpha
_cod_original_cell_volume        493.7(3)
_cod_database_code               4321677