The <i>P</i>4~3~ enantiomorph of Sr~2~As~2~O~7~
Mbarek, Aicha; Edhokkar, Fadhila; Acta Crystallographica Section E 69 (2013) i84–; doi:10.1107/S1600536813031619

data_2238938
_publ_section_title
;
 The <i>P</i>4~3~ enantiomorph of Sr~2~As~2~O~7~
;
_journal_issue                   12
_journal_name_full               'Acta Crystallographica Section E'
_journal_page_first              i84
_journal_paper_doi               10.1107/S1600536813031619
_journal_volume                  69
_journal_year                    2013
_chemical_formula_iupac          'Sr2 As2 O7'
_chemical_formula_moiety         'Sr2 As2 O7'
_chemical_formula_sum            'As2 O7 Sr2'
_chemical_formula_weight         437.08
_chemical_name_common            Sr2As2O7
_chemical_name_systematic
;
Strontium diarsenate
;
_space_group_crystal_system      tetragonal
_space_group_IT_number           78
_space_group_name_Hall           'P 4cw'
_space_group_name_H-M_alt        'P 43'
_symmetry_space_group_name_Hall  'P 4cw'
_symmetry_space_group_name_H-M   'P 43'
_audit_creation_method           SHELXL-2013
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            8
_cell_length_a                   7.10890(10)
_cell_length_b                   7.10890(10)
_cell_length_c                   25.6160(4)
_cell_measurement_reflns_used    8103
_cell_measurement_temperature    296(2)
_cell_measurement_theta_max      33.16
_cell_measurement_theta_min      3.28
_cell_volume                     1294.54(3)
_computing_cell_refinement       'SAINT (Bruker, 2008)'
_computing_data_collection       'APEX2 (Bruker, 2008)'
_computing_data_reduction        'SAINT (Bruker, 2008)'
_computing_molecular_graphics
;
DIAMOND (Brandenburg, 1999) and ORTEP-3 for Windows (Farrugia,
2012)
;
_computing_publication_material  'SHELXTL (Sheldrick, 2008)'
_computing_structure_refinement  'SHELXL2013 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      296(2)
_diffrn_detector_area_resol_mean 8.3333
_diffrn_measured_fraction_theta_full 0.997
_diffrn_measured_fraction_theta_max 0.997
_diffrn_measurement_device_type  'Bruker APEXII CCD'
_diffrn_measurement_method       '\w and \f'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0354
_diffrn_reflns_limit_h_max       10
_diffrn_reflns_limit_h_min       -10
_diffrn_reflns_limit_k_max       10
_diffrn_reflns_limit_k_min       -6
_diffrn_reflns_limit_l_max       39
_diffrn_reflns_limit_l_min       -39
_diffrn_reflns_number            18524
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         33.217
_diffrn_reflns_theta_min         2.865
_exptl_absorpt_coefficient_mu    26.615
_exptl_absorpt_correction_T_max  0.7513
_exptl_absorpt_correction_T_min  0.4480
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   '(<i>SADABS</i>; Bruker, 2008)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    4.485
_exptl_crystal_description       block
_exptl_crystal_F_000             1584
_exptl_crystal_size_max          0.753
_exptl_crystal_size_mid          0.431
_exptl_crystal_size_min          0.144
_refine_diff_density_max         0.916
_refine_diff_density_min         -1.343
_refine_ls_abs_structure_details 'Flack (1983), 2400 Friedel pairs'
_refine_ls_abs_structure_Flack   0.037(8)
_refine_ls_extinction_coef       0.00348(16)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     'SHELXL2013 (Sheldrick, 2008)'
_refine_ls_goodness_of_fit_ref   1.014
_refine_ls_hydrogen_treatment    undef
_refine_ls_matrix_type           full
_refine_ls_number_parameters     201
_refine_ls_number_reflns         4930
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.014
_refine_ls_R_factor_all          0.0254
_refine_ls_R_factor_gt           0.0218
_refine_ls_shift/su_max          0.021
_refine_ls_shift/su_mean         0.003
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0055P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0427
_refine_ls_wR_factor_ref         0.0437
_reflns_number_gt                4593
_reflns_number_total             4930
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            wm2770.cif
_cod_data_source_block           I
_cod_original_cell_volume        1294.54(4)
_cod_database_code               2238938
_shelx_hkl_checksum              35918
_shelx_res_checksum              30218
_shelxl_version_number           2.013