Niobium-Arsenic Zintl Phases: A6NbAs5 (A = K, Rb, Cs), K6NbTlAs4, and K8NbPbAs5 with Edge-Bridged Niobium-Centered Tetrahedra of Arsenic, [NbAs4M]n- Where M = As, Tl, Pb
Franck Gascoin; Slavi C. Sevov; Inorganic Chemistry 41 (2002) 2820–2825; doi:10.1021/ic020036n

data_4318039
_publ_section_title
;
 Niobium-Arsenic Zintl Phases: A6NbAs5 (A = K, Rb, Cs), K6NbTlAs4, and
 K8NbPbAs5 with Edge-Bridged Niobium-Centered Tetrahedra of Arsenic,
 [NbAs4M]n- Where M = As, Tl, Pb
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_journal_name_full               'Inorganic Chemistry'
_journal_page_first              2820
_journal_page_last               2825
_journal_paper_doi               10.1021/ic020036n
_journal_volume                  41
_journal_year                    2002
_chemical_formula_moiety         K6TlNbAs4
_chemical_formula_sum            'As4 K6 Nb Tl'
_chemical_formula_weight         831.56
_chemical_name_common            K6TlNbAs4
_chemical_name_systematic
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  ?
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_space_group_IT_number           62
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  '-P 2ac 2n'
_symmetry_space_group_name_H-M   'P n m a'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   18.7860(10)
_cell_length_b                   10.4442(4)
_cell_length_c                   7.7150(10)
_cell_measurement_reflns_used    25
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      12
_cell_measurement_theta_min      10
_cell_volume                     1513.7(2)
_computing_cell_refinement       CAD4_(Enraf-Nonius,_1977
_computing_data_collection       CAD4_(Enraf-Nonius,_1977
_computing_data_reduction        SDS_Package_(Enraf-Nonius,_1985
_computing_molecular_graphics    'Bruker SHELXTL-V5.1'
_computing_publication_material  'Bruker SHELXTL-V5.1'
_computing_structure_refinement  'Bruker SHELXTL-V5.1'
_computing_structure_solution    'Bruker SHELXTL-V5.1'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.852
_diffrn_measured_fraction_theta_max 0.852
_diffrn_measurement_device_type  Enraf-Nonius_CAD4
_diffrn_measurement_method       omega-2theta
_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  0.0000
_diffrn_reflns_av_sigmaI/netI    0.0368
_diffrn_reflns_limit_h_max       22
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       0
_diffrn_reflns_limit_k_min       -12
_diffrn_reflns_limit_l_max       9
_diffrn_reflns_limit_l_min       0
_diffrn_reflns_number            1207
_diffrn_reflns_theta_full        24.99
_diffrn_reflns_theta_max         24.99
_diffrn_reflns_theta_min         2.85
_diffrn_standards_interval_count 200
_diffrn_standards_interval_time  120
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    21.671
_exptl_absorpt_correction_T_max  0.7416
_exptl_absorpt_correction_T_min  0.2250
_exptl_absorpt_correction_type   semi-empirical
_exptl_absorpt_process_details   'four psi-scans'
_exptl_crystal_colour            black
_exptl_crystal_density_diffrn    3.649
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             1472
_exptl_crystal_size_max          0.18
_exptl_crystal_size_mid          0.18
_exptl_crystal_size_min          0.04
_refine_diff_density_max         0.879
_refine_diff_density_min         -0.895
_refine_diff_density_rms         0.235
_refine_ls_extinction_coef       0.00069(9)
_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   1.085
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     65
_refine_ls_number_reflns         1207
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.085
_refine_ls_R_factor_all          0.0479
_refine_ls_R_factor_gt           0.0335
_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^)+(0.0372P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0713
_refine_ls_wR_factor_ref         0.0762
_reflns_number_gt                997
_reflns_number_total             1207
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ic020036n_2.cif
_cod_data_source_block           K6TlNbAs4
_cod_depositor_comments
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The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Orthorhombic' changed to
'orthorhombic' according to the built-in table from CIF Core
dictionary named 'cif_core.dic' version 2.4.1 from 2010-06-29.

Automatic conversion script
Id: cif_fix_values 1646 2011-03-28 12:23:43Z adriana 
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_cod_database_code               4318039