Average grossite crystal structure
Efremov, V. A.; Gutnikov, S. I.; Kartashov, A. A.; Lazoryak, B.I.; Personal communication to COD  (2012) –; doi:

data_3500014
_publ_section_exptl_prep
; The mixture with a stoichiometric ratio of calcium carbonate and aluminum 
oxide was ground and annealed three times for 24 hours at 1600 \%C. After every
annealing the mixture was ground again.
;
_publ_section_references
;Petricek, V., Dusek, M. & Palatinus L. (2006). Jana2006.
Structure Determination Software Programs.
Institute of Physics, Praha, Czech Republic.

Palatinus L. & Chapuis G. (2007). J. Appl. Cryst. 40, 786-790.

Altomare, A., Burla, M.C., Giacovazzo, C., Guagliardi, A., Moliterni, A.G.G., 
Polidori G., Rizzi R. (2001). J. Appl. Cryst. 34, 392-397.

Larson A.C., Von Dreele R.B. (2004). 
General Structure Analysis System (GSAS) 
Los Alamos National Laboratory Report LAUR, 86-748

Toby B.H. (2001). J. Appl. Cryst. 34, 210-221.

Luterotti L., Bortolotti M.  (2003). IUCr: Compcomm Newsletter 1, 43-50.
;
_publ_section_title
;
 Average grossite crystal structure
;
_journal_name_full               'Personal communication to COD'
_journal_year                    2012
_chemical_compound_source        synthetic
_chemical_formula_moiety         'Al4 O7, Ca'
_chemical_formula_structural
;
Ca (Al4 O7)
;
_chemical_formula_sum            'Al4 Ca O7'
_chemical_formula_weight         260
_chemical_name_common            'Calcium dialuminate'
_chemical_name_mineral           Grossite
_chemical_name_systematic        ' tetraaluminium calcium heptaoxide'
_space_group_IT_number           15
_symmetry_cell_setting           monoclinic
_symmetry_Int_Tables_number      15
_symmetry_space_group_name_Hall  '-C 2yc'
_symmetry_space_group_name_H-M   'C 1 2/c 1'
_audit_creation_method           'Jana2006 Version : 04/07/2012'
_cell_angle_alpha                90
_cell_angle_beta                 106.905(6)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   12.886(6)
_cell_length_b                   8.8830(12)
_cell_length_c                   5.4423(27)
_cell_measurement_reflns_used    311
_cell_measurement_temperature    295
_cell_measurement_theta_max      100
_cell_measurement_theta_min      10
_cell_special_details
; Cell parameters was refined by full-profile analysis (Jana2006, GSAS,
Moud, Quanto). Pseudo-Voigt function was used as profile function.
Pearson VII function was used in addition (in Quanto only).
Cell parameters determined as the weighted average of 85 calculations 
(17 samples x 5 methods). Grossite mass fraction was used as a weight.
;
_cell_volume                     596.0(4)
_computing_cell_refinement
'Jana2006 (Petricek, Dusek & Palatinus, 2006)'
_computing_data_collection       'Huber software'
_computing_data_reduction        'XRUtils (Efremov,private)'
_computing_molecular_graphics    'VESTA 3 ( Momma & Izumi, 2011 )'
_computing_structure_refinement
'Jana2006 (Petricek, Dusek & Palatinus, 2006)'
_computing_structure_solution    'Superflip (Palatinus & Chapuis, 2007)'
_diffrn_ambient_temperature      295
_diffrn_detector                 'Image plate'
_diffrn_detector_type            Huber
_diffrn_measurement_device       'Guinier powder diffractometer'
_diffrn_radiation_monochromator  'curved Ge 111'
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           'Cu K\a~1~'
_diffrn_radiation_wavelength     1.540598
_diffrn_source                   'sealed x-ray tube'
_diffrn_source_target            Cu
_exptl_absorpt_coefficient_mu    14.972
_exptl_crystal_density_diffrn    2.898
_exptl_crystal_F_000             512
_pd_char_colour                  colourless
_pd_meas_2theta_range_inc        0.01
_pd_meas_2theta_range_max        100.000
_pd_meas_2theta_range_min        3.500
_pd_meas_number_of_points        9651
_pd_meas_scan_method             fixed
_pd_meas_special_details
; Sum of 3 measurements 20 min each (total 60 min),
Number of measurement points 20001. Step size (2-Theta) 0.005
;
_pd_proc_2theta_range_inc        0.01
_pd_proc_2theta_range_max        100
_pd_proc_2theta_range_min        9.47
_pd_proc_info_data_reduction
; A number of intensities 
values was reduced by using triangular smooth. The principle of this method is 
the averaging of the experimental intensities, that separated by "doubling"
step-size away from each other by Ij =( I2j-1 + 2*I2j + I2j+1)/4). x-ray
camera geometric factor (G=cos(2*theta-beta)), beta = 45) was added.
;
_pd_proc_ls_special_details
;Atom sites was calculated as an average of 
jana2006 (RF% = 3.32, Rw% = 3.45, GOF = 1.05, Rp% = 2.57, Rwp% = 3.37) and 
GSAS (RF% = 4.58, Rw% = 5.97, GOF = 1, Rp% = 2.52, Rwp% = 3.25) data. 
;
_pd_spec_mount_mode              transmission
_pd_spec_shape                   flat_sheet
_pd_spec_size_thick              0.05
_refine_special_details
;background approximation: 12 Legendre polynomials (jana2006),
shifted Chebyshev function of 1st kind with 12 terms. (GSAS)
;
_cod_data_source_file            Grossite_Mean.cif
_cod_data_source_block           global
_cod_original_sg_symbol_H-M      'C 2/c'
_cod_database_code               3500014