The alluaudite-like arsenate NaCaMg~3~(AsO~4~)~3~
Haj Abdallah, Anissa; Haddad, Amor; Acta Crystallographica Section E 64 (2008) i36–; doi:10.1107/S1600536808014633

data_2218318
_publ_section_title
;
 The alluaudite-like arsenate NaCaMg~3~(AsO~4~)~3~
;
_journal_coeditor_code           BR2069
_journal_issue                   6
_journal_name_full               'Acta Crystallographica Section E'
_journal_page_first              i36
_journal_paper_doi               10.1107/S1600536808014633
_journal_volume                  64
_journal_year                    2008
_chemical_formula_iupac          'Na Ca Mg3 (As O4)3'
_chemical_formula_structural     'Na Ca Mg3 (As O4)3'
_chemical_formula_sum            'As3 Ca Mg3 Na O12'
_chemical_formula_weight         552.74
_chemical_name_systematic
;
Sodium calcium trimagnesium tris(arsenate)
;
_space_group_IT_number           15
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-C 2yc'
_symmetry_space_group_name_H-M   'C 1 2/c 1'
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 112.450(10)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   11.8800(10)
_cell_length_b                   12.8170(10)
_cell_length_c                   6.741(2)
_cell_measurement_reflns_used    25
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      28
_cell_measurement_theta_min      2.4
_cell_volume                     948.6(3)
_computing_cell_refinement
'CAD-4 EXPRESS (Duisenberg, 1992; Mac\'i\<cek & Yordanov, 1992)'
_computing_data_collection
'CAD-4 EXPRESS (Duisenberg, 1992; Mac\'i\<cek & Yordanov, 1992)'
_computing_data_reduction        'Molen (Fair, 1990)'
_computing_molecular_graphics    'DIAMOND (Brandenburg, 1998)'
_computing_publication_material  'SHELXL97 (Sheldrick, 2008)'
_computing_structure_refinement  'SHELXL97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS86 (Sheldrick, 2008)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_device_type  'Enraf--Nonius CAD-4'
_diffrn_measurement_method       \w/2\q
_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  0.0214
_diffrn_reflns_av_sigmaI/netI    0.0121
_diffrn_reflns_limit_h_max       14
_diffrn_reflns_limit_h_min       -15
_diffrn_reflns_limit_k_max       16
_diffrn_reflns_limit_k_min       -1
_diffrn_reflns_limit_l_max       8
_diffrn_reflns_limit_l_min       0
_diffrn_reflns_number            1358
_diffrn_reflns_theta_full        27.96
_diffrn_reflns_theta_max         27.96
_diffrn_reflns_theta_min         2.44
_diffrn_standards_decay_%        0.4
_diffrn_standards_interval_time  120
_diffrn_standards_number         2
_exptl_absorpt_coefficient_mu    11.364
_exptl_absorpt_correction_T_max  0.1798
_exptl_absorpt_correction_T_min  0.1104
_exptl_absorpt_correction_type   psi-scan
_exptl_absorpt_process_details   '(North <i>et al.</i>,  1968)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    3.870
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prismatic
_exptl_crystal_F_000             1048
_exptl_crystal_size_max          0.6
_exptl_crystal_size_mid          0.2
_exptl_crystal_size_min          0.15
_refine_diff_density_max         0.994
_refine_diff_density_min         -0.997
_refine_ls_extinction_coef       0.0071(4)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     'SHELXL97 (Sheldrick, 2008)'
_refine_ls_goodness_of_fit_ref   1.289
_refine_ls_matrix_type           full
_refine_ls_number_parameters     100
_refine_ls_number_reflns         1154
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.289
_refine_ls_R_factor_all          0.0228
_refine_ls_R_factor_gt           0.0223
_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^)+(0.0244P)^2^+8.0874P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0603
_refine_ls_wR_factor_ref         0.0604
_reflns_number_gt                1133
_reflns_number_total             1154
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            br2069.cif
_cod_data_source_block           I
_cod_original_cell_volume        948.7(3)
_cod_original_sg_symbol_H-M      'C 2/c'
_cod_database_code               2218318
_cod_database_fobs_code          2218318