Ca~4~As~3~ ‒ a new binary calcium arsenide
Hoffmann, Andrea V.; Hlukhyy, Viktor; Fässler, Thomas F.; Acta Crystallographica Section E 71 (2015) 1548–1550; doi:10.1107/S2056989015022367

data_2241363
_publ_section_title
;
 Ca~4~As~3~ -- a new binary calcium arsenide
;
_journal_coeditor_code           RU2065
_journal_issue                   12
_journal_name_full               'Acta Crystallographica Section E'
_journal_page_first              1548
_journal_page_last               1550
_journal_paper_doi               10.1107/S2056989015022367
_journal_volume                  71
_journal_year                    2015
_chemical_formula_iupac          'Ca4 As3'
_chemical_formula_moiety         'Ca4 As3'
_chemical_formula_sum            'As3 Ca4'
_chemical_formula_weight         385.08
_chemical_name_systematic
;
Tetracalcium triarsenide
;
_space_group_IT_number           55
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  '-P 2 2ab'
_symmetry_space_group_name_H-M   'P b a m'
_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            8
_cell_length_a                   11.5137(5)
_cell_length_b                   12.0584(6)
_cell_length_c                   10.3426(4)
_cell_measurement_reflns_used    2659
_cell_measurement_temperature    150(2)
_cell_measurement_theta_max      32.8702
_cell_measurement_theta_min      3.3712
_cell_volume                     1435.93(11)
_computing_cell_refinement
;
CrysAlis RED (Oxford Diffraction, 2009)
;
_computing_data_collection
;
CrysAlis CCD (Oxford Diffraction, 2009)
;
_computing_data_reduction
;
CrysAlis RED (Oxford Diffraction, 2009)
;
_computing_molecular_graphics
;
DIAMOND (Brandenburg, 2012)
;
_computing_structure_refinement
;
SHELXL97 (Sheldrick, 2008)
;
_computing_structure_solution
;
SHELXS97 (Sheldrick, 2008)
;
_diffrn_ambient_temperature      150(2)
_diffrn_detector_area_resol_mean 16.0238
_diffrn_measured_fraction_theta_full 0.940
_diffrn_measured_fraction_theta_max 0.940
_diffrn_measurement_device_type  'Oxford Diffraction Xcalibur 3'
_diffrn_measurement_method       '\w and \p scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'Enhance (Mo) X-ray Source'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.1433
_diffrn_reflns_av_sigmaI/netI    0.1740
_diffrn_reflns_limit_h_max       17
_diffrn_reflns_limit_h_min       -17
_diffrn_reflns_limit_k_max       18
_diffrn_reflns_limit_k_min       -18
_diffrn_reflns_limit_l_max       14
_diffrn_reflns_limit_l_min       -14
_diffrn_reflns_number            26414
_diffrn_reflns_theta_full        32.95
_diffrn_reflns_theta_max         32.8702
_diffrn_reflns_theta_min         3.3712
_exptl_absorpt_coefficient_mu    16.614
_exptl_absorpt_correction_T_max  1.00000
_exptl_absorpt_correction_T_min  0.68248
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
(CrysAlis RED; Oxford Diffraction, 2009)
;
_exptl_crystal_colour            'metallic dark grey'
_exptl_crystal_density_diffrn    3.563
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       needle
_exptl_crystal_F_000             1432
_exptl_crystal_size_max          0.08
_exptl_crystal_size_mid          0.04
_exptl_crystal_size_min          0.01
_refine_diff_density_max         1.949
_refine_diff_density_min         -1.556
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.680
_refine_ls_matrix_type           full
_refine_ls_number_parameters     74
_refine_ls_number_reflns         2659
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      0.680
_refine_ls_R_factor_all          0.0991
_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^)+(0.0138P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0481
_refine_ls_wR_factor_ref         0.0537
_reflns_number_gt                1273
_reflns_number_total             2659
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ru2065sup1.cif
_cod_data_source_block           I
_cod_database_code               2241363
_cod_database_fobs_code 2241363