The 3R polymorph of CaSi2
Nedumkandathil, Reji; Benson, Daryn E.; Grins, Jekabs; Spektor, Kristina; Häussermann, Ulrich; Journal of Solid State Chemistry 222 (2015) 18–24; doi:10.1016/j.jssc.2014.10.033

data_1562110
_publ_section_title
;
 The 3R polymorph of CaSi2
;
_journal_name_full               'Journal of Solid State Chemistry'
_journal_page_first              18
_journal_page_last               24
_journal_paper_doi               10.1016/j.jssc.2014.10.033
_journal_volume                  222
_journal_year                    2015
_chemical_formula_moiety         'Ca Si2'
_chemical_formula_structural     'Ca Si2'
_chemical_formula_sum            'Ca Si2'
_chemical_formula_weight         96.25
_chemical_name_systematic
; 
Calcium Silicide
;
_space_group_IT_number           166
_space_group_name_Hall           '-R 3 2"'
_space_group_name_H-M_alt        'R -3 m :H'
_symmetry_cell_setting           trigonal
_symmetry_space_group_name_Hall  '-R 3 2"'
_symmetry_space_group_name_H-M   'R -3 m :H'
_cell_angle_alpha                90.00000
_cell_angle_beta                 90.00000
_cell_angle_gamma                120.00000
_cell_formula_units_Z            3
_cell_length_a                   3.82844(13)
_cell_length_b                   3.82843(13)
_cell_length_c                   15.89661(71)
_cell_volume                     201.780(13)
_computing_publication_material  FULLPROF,JANA2006
_computing_structure_refinement  FULLPROF
_diffrn_ambient_temperature      298
_diffrn_radiation_type           X-ray
_diffrn_radiation_wavelength     0.207059
_diffrn_source
;'Petra III synchrotron radiation source,
  High Resolution Powder Diffraction Beamline P02.1, Undulator U23'
;
_exptl_absorpt_coefficient_mu    0.0
_exptl_crystal_density_diffrn    2.376
_exptl_crystal_density_method    'not measured'
_pd_char_colour                  'dark gray metallic'
_pd_instr_location
;  PETRA III facility
   DESY Photon Science
   Notkestr. 85
   D-22607 HAMBURG
   Germany
;
_pd_meas_2theta_range_inc        0.004528
_pd_meas_2theta_range_max        9.23757
_pd_meas_2theta_range_min        1.53168
_pd_meas_number_of_points        1704
_pd_meas_scan_method             cont
_pd_prep_pressure                3000
_pd_prep_temperature             400
_pd_proc_2theta_range_inc        0.004528
_pd_proc_2theta_range_max        9.2403
_pd_proc_2theta_range_min        1.5344
_pd_proc_ls_background_function  "'Linear interpolation between 41 points'"
_pd_proc_ls_pref_orient_corr     ' 'March-Dollase model"'
_pd_proc_ls_profile_function
; 7
 (Thompson-Cox-Hastings pseudo-Voigt function convoluted with 
 axial divergence asymmetry function: J. Appl. Cryst. 
 (1994). 27, 892)
;
_pd_proc_ls_prof_R_factor        5.1959
_pd_proc_ls_prof_wR_expected     12.7343
_pd_proc_ls_prof_wR_factor       7.8185
_pd_proc_wavelength              0.207059
_pd_spec_mounting                ' 'capillary''
_pd_spec_mount_mode              transmission
_pd_spec_shape                   cylinder
_pd_spec_size_equat              0.5
_refine_ls_number_parameters     59
_refine_ls_number_reflns         24
_refine_ls_number_restraints     0
_refine_ls_R_I_factor            4.6937
_cod_data_source_file            JSSC-2015-222-18.cif
_cod_data_source_block           CaSi2_3R
_cod_depositor_comments
;
The following automatic conversions were performed:

data item '_diffrn_ambient_temperature' value '298K' was changed to
'298' -- the value should be numeric and without a unit designator.

data item '_symmetry_cell_setting' value 'Trigonal' was changed to
'trigonal' in accordance with the built-in table derived from the CIF
Core dictionary named 'cif_core.dic' version 2.4.5 last updated on
2014-11-21.

Automatic conversion script
Id: cif_fix_values 8369 2020-08-20 11:38:08Z andrius 
;
_cod_original_sg_symbol_H-M      'R -3 m'
_cod_original_formula_sum        'Ca1 Si2'
_cod_database_code               1562110
_pd_proc_ls_prof_cr_factor       12.2333
_pd_proc_ls_prof_cwr_factor      13.3190
_pd_proc_ls_prof_cwr_expected    21.6932
_pd_proc_ls_prof_chi2            0.3770
_pd_proc_ls_prof_echi2           0.4555