Armel Le Bail; Personal communication to COD  (2016) –; doi:

data_3500038
_journal_name_full               'Personal communication to COD'
_journal_year                    2016
_chemical_formula_sum            'C4 H4 Ca O6'
_chemical_formula_weight         188.149
_chemical_name_systematic
;
Calcium tartrate anhydrous form II
;
_space_group_IT_number           20
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  'C 2c 2'
_symmetry_space_group_name_H-M   'C 2 2 21'
_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                   7.618(8)
_cell_length_b                   9.945(16)
_cell_length_c                   7.219(4)
_cell_measurement_temperature    293(2)
_cell_volume                     546.9(11)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.995
_diffrn_measured_fraction_theta_max 0.995
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71069
_diffrn_reflns_av_R_equivalents  0.0726
_diffrn_reflns_av_sigmaI/netI    0.0850
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       -12
_diffrn_reflns_limit_l_max       9
_diffrn_reflns_limit_l_min       -9
_diffrn_reflns_number            757
_diffrn_reflns_theta_full        27.33
_diffrn_reflns_theta_max         27.33
_diffrn_reflns_theta_min         3.37
_exptl_absorpt_coefficient_mu    1.103
_exptl_crystal_density_diffrn    2.285
_exptl_crystal_density_method    'not measured'
_exptl_crystal_F_000             376
_exptl_special_details
;
Synthesis:
Acide tartrique : 3.10-3 mole  soit 0.4503 g
NaOH (6 mol/L, soit 12 g dans 50 mL) : 3.10-3 mole soit 1 mL
CaCl2.2H2O : 3.10-3 mole  soit 0.4410 g
15 mL Eau

X-ray measurement october 2008

Unpublished
;
_refine_diff_density_max         0.669
_refine_diff_density_min         -0.521
_refine_diff_density_rms         0.123
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.07(14)
_refine_ls_extinction_coef       0.002(3)
_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   1.149
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     56
_refine_ls_number_reflns         624
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.148
_refine_ls_R_factor_all          0.0927
_refine_ls_R_factor_gt           0.0532
_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^)+(0.0539P)^2^+1.1037P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1162
_refine_ls_wR_factor_ref         0.1342
_refine_special_details
;
 Refinement of F^2^ against ALL reflections.  The weighted R-factor wR and
 goodness of fit S are based on F^2^, conventional R-factors R are based
 on F, with F set to zero for negative F^2^. The threshold expression of
 F^2^ > 2sigma(F^2^) is used only for calculating R-factors(gt) etc. and is
 not relevant to the choice of reflections for refinement.  R-factors based
 on F^2^ are statistically about twice as large as those based on F, and R-
 factors based on ALL data will be even larger.
;
_reflns_number_gt                484
_reflns_number_total             624
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            vmmw65f.cif
_cod_data_source_block           vmmw65f
_cod_database_code               3500038
_cod_database_fobs_code 3500038