NaMg~4~(AsO~4~)~3~
Anissa, Haj Abdallah; Brahim, Ayed; Amor, Haddad; Acta Crystallographica, Section E 60 (2004) i77–i79; doi:10.1107/S1600536804012772

data_2203846
_publ_section_title
;
NaMg~4~(AsO~4~)~3~
;
_journal_issue                   7
_journal_name_full               'Acta Crystallographica, Section E'
_journal_page_first              i77
_journal_page_last               i79
_journal_paper_doi               10.1107/S1600536804012772
_journal_volume                  60
_journal_year                    2004
_chemical_formula_iupac          'Na Mg4 (As O4)3'
_chemical_formula_structural     'Na Mg4 (As O4)3'
_chemical_formula_sum            'As3 Mg4 Na O12'
_chemical_formula_weight         536.96
_chemical_name_common            'Na Mg4 (As O4)3'
_chemical_name_systematic
;
Sodium tetramagnesium tris(arsenate)
;
_space_group_IT_number           122
_space_group_name_Hall           'I -4 2bw'
_space_group_name_H-M_alt        'I -4 2 d'
_symmetry_cell_setting           tetragonal
_symmetry_space_group_name_Hall  'I -4 2bw'
_symmetry_space_group_name_H-M   'I -4 2 d'
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL97
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   6.8170(10)
_cell_length_b                   6.8170(10)
_cell_length_c                   19.242(3)
_cell_measurement_reflns_used    25
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      27
_cell_measurement_theta_min      2
_cell_volume                     894.2(2)
_computing_cell_refinement       'CAD-4 EXPRESS'
_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
_computing_structure_refinement  'SHELXL97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS86 (Sheldrick, 1990)'
_database_code_amcsd             0010433
_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  0.0314
_diffrn_reflns_av_sigmaI/netI    0.0351
_diffrn_reflns_limit_h_max       4
_diffrn_reflns_limit_h_min       -8
_diffrn_reflns_limit_k_max       8
_diffrn_reflns_limit_k_min       -1
_diffrn_reflns_limit_l_max       25
_diffrn_reflns_limit_l_min       -1
_diffrn_reflns_number            1111
_diffrn_reflns_theta_full        27.93
_diffrn_reflns_theta_max         27.93
_diffrn_reflns_theta_min         3.17
_diffrn_standards_decay_%        0.4
_diffrn_standards_interval_time  120
_diffrn_standards_number         2
_exptl_absorpt_coefficient_mu    11.553
_exptl_absorpt_correction_T_max  0.630
_exptl_absorpt_correction_T_min  0.394
_exptl_absorpt_correction_type   '\y scan'
_exptl_absorpt_process_details   '(North et al., 1968)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    3.989
_exptl_crystal_density_meas      ?
_exptl_crystal_density_method    .
_exptl_crystal_description       prismatic
_exptl_crystal_F_000             1016
_exptl_crystal_size_max          0.1
_exptl_crystal_size_mid          0.07
_exptl_crystal_size_min          0.04
_refine_diff_density_max         0.389
_refine_diff_density_min         -0.488
_refine_ls_abs_structure_details 'Flack (1983), with xx Friedel pairs'
_refine_ls_abs_structure_Flack   -0.003(17)
_refine_ls_extinction_coef       0.0016(3)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     'SHELXL97 (Sheldrick, 1997)'
_refine_ls_goodness_of_fit_ref   1.097
_refine_ls_hydrogen_treatment    none
_refine_ls_matrix_type           full
_refine_ls_number_parameters     48
_refine_ls_number_reflns         525
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.097
_refine_ls_R_factor_all          0.0206
_refine_ls_R_factor_gt           0.0181
_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^)+(0.0194P)^2^] where P = (Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0444
_refine_ls_wR_factor_ref         0.0450
_reflns_number_gt                500
_reflns_number_total             525
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            br6150.cif
_cod_database_code               2203846
_amcsd_formula_title             NaMg4(AsO4)3