Quaternary rare-earth arsenides REAg1−Zn As2 (RE=La‒Nd, Sm, Gd‒Dy) with tetragonal SrZnBi2- and HfCuSi2-type structures
Ramachandran, Krishna K.; Genet, Clément; Mar, Arthur; Journal of Solid State Chemistry 231 (2015) 204–211; doi:10.1016/j.jssc.2015.08.032

data_1561726
_publ_section_title
;
 Quaternary rare-earth arsenides REAg1&#x2212;Zn As2 (RE=La--Nd, Sm,
 Gd--Dy) with tetragonal SrZnBi2- and HfCuSi2-type structures
;
_journal_name_full               'Journal of Solid State Chemistry'
_journal_page_first              204
_journal_page_last               211
_journal_paper_doi               10.1016/j.jssc.2015.08.032
_journal_volume                  231
_journal_year                    2015
_chemical_formula_structural     'La Ag0.50 Zn0.50 As2'
_chemical_formula_sum            'Ag0.5 As2 La Zn0.5'
_chemical_formula_weight         375.37
_chemical_name_common
'lanthanum silver zinc arsenide (1/0.5/0.5/2)'
_chemical_name_systematic
'lanthanum silver zinc arsenide (1/0.5/0.5/2)'
_space_group_crystal_system      tetragonal
_space_group_IT_number           139
_space_group_name_Hall           '-I 4 2'
_space_group_name_H-M_alt        'I 4/m m m'
_atom_sites_solution_hydrogens   .
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-2013
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   4.1300(2)
_cell_length_b                   4.1300(2)
_cell_length_c                   20.8160(11)
_cell_measurement_reflns_used    2696
_cell_measurement_temperature    296(2)
_cell_measurement_theta_max      33.06
_cell_measurement_theta_min      3.92
_cell_volume                     355.06(3)
_computing_cell_refinement       'Bruker SAINT 8.34A (Bruker, 2013)'
_computing_data_collection       'Bruker APEX 2 (Bruker, 2008)'
_computing_data_reduction        'Bruker SAINT 8.34A'
_computing_molecular_graphics    'ATOMS 5.1 (Dowty, 1999)'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-2013 (Sheldrick, 2013)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      296(2)
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 0.996
_diffrn_measurement_device_type  'Bruker PLATFORM/SMART APEX II CCD'
_diffrn_measurement_method       '\w and \f scans'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0261
_diffrn_reflns_av_unetI/netI     0.0141
_diffrn_reflns_Laue_measured_fraction_full 1.000
_diffrn_reflns_Laue_measured_fraction_max 0.996
_diffrn_reflns_limit_h_max       6
_diffrn_reflns_limit_h_min       -6
_diffrn_reflns_limit_k_max       6
_diffrn_reflns_limit_k_min       -6
_diffrn_reflns_limit_l_max       31
_diffrn_reflns_limit_l_min       -31
_diffrn_reflns_number            2499
_diffrn_reflns_point_group_measured_fraction_full 1.000
_diffrn_reflns_point_group_measured_fraction_max 0.996
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         33.057
_diffrn_reflns_theta_min         1.957
_diffrn_source                   'fine-focus sealed tube'
_exptl_absorpt_coefficient_mu    36.220
_exptl_absorpt_correction_T_max  0.2396
_exptl_absorpt_correction_T_min  0.0623
_exptl_absorpt_correction_type   numerical
_exptl_absorpt_process_details   'Bruker SHELXTL (Sheldrick, 2013)'
_exptl_crystal_colour            black
_exptl_crystal_density_diffrn    7.022
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       irregular
_exptl_crystal_F_000             646
_exptl_crystal_size_max          0.121
_exptl_crystal_size_mid          0.116
_exptl_crystal_size_min          0.078
_refine_diff_density_max         1.124
_refine_diff_density_min         -0.772
_refine_diff_density_rms         0.192
_refine_ls_extinction_coef       0.0122(5)
_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   1.144
_refine_ls_hydrogen_treatment    undef
_refine_ls_matrix_type           full
_refine_ls_number_parameters     13
_refine_ls_number_reflns         248
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.144
_refine_ls_R_factor_all          0.0136
_refine_ls_R_factor_gt           0.0134
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0092P)^2^+2.4955P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0306
_refine_ls_wR_factor_ref         0.0307
_reflns_Friedel_coverage         0.000
_reflns_Friedel_fraction_full    .
_reflns_Friedel_fraction_max     .
_reflns_number_gt                245
_reflns_number_total             248
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            JSSC-2015-231-204.cif
_cod_data_source_block           LaAgZnAs-unsplit
_cod_original_cell_volume        355.06(4)
_cod_original_formula_sum        'Ag0.50 As2 La Zn0.50'
_cod_database_code               1561726
_shelx_estimated_absorpt_t_min   0.097
_shelx_estimated_absorpt_t_max   0.164
_shelxl_version_number           2013-4
_shelx_res_checksum              2020
_shelx_hkl_checksum              22202