Crystal structures of deuterated sodium molybdate dihydrate and sodium tungstate dihydrate from time-of-flight neutron powder diffraction
Fortes, A. Dominic; Acta Crystallographica Section E 71 (2015) 799–806; doi:10.1107/S2056989015011354

data_2240858
_publ_section_title
;
 Crystal structures of deuterated sodium molybdate dihydrate and sodium
 tungstate dihydrate from time-of-flight neutron powder diffraction
;
_journal_coeditor_code           WM5172
_journal_issue                   7
_journal_name_full               'Acta Crystallographica Section E'
_journal_page_first              799
_journal_page_last               806
_journal_paper_doi               10.1107/S2056989015011354
_journal_volume                  71
_journal_year                    2015
_chemical_formula_iupac          'Na2 W O4, 2D2 O'
_chemical_formula_moiety         'W O4, 2(D2 O), 2(Na)'
_chemical_formula_structural     'Na2 W O6 D4'
_chemical_formula_sum            'D4 Na2 O6 W'
_chemical_formula_weight         333.872
_chemical_melting_point          373
_chemical_name_common            'sodium tungstate dihydrate'
_chemical_name_systematic
;
Disodium tungsten(VI) oxide dihydrate
;
_space_group_IT_number           61
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  '-P 2ac 2ab'
_symmetry_space_group_name_H-M   'P b c a'
_audit_creation_method           'from EXP file using GSAS2CIF'
_cell_angle_alpha                90.0
_cell_angle_beta                 90.0
_cell_angle_gamma                90.0
_cell_formula_units_Z            8
_cell_length_a                   8.482514(15)
_cell_length_b                   10.595156(19)
_cell_length_c                   13.85640(3)
_cell_measurement_temperature    295
_cell_volume                     1245.324(4)
_computing_cell_refinement
;
GSAS/Expgui (Larsen & Von Dreele, 2000: Toby, 2001)
;
_computing_data_collection       'HRPD control software'
_computing_data_reduction
;
Mantid (Arnold <i>et al</i>., 2014: Mantid, 2013)
;
_computing_molecular_graphics
;
DIAMOND (Putz & Brandenburg, 2006)
;
_computing_publication_material
;
publCIF (Westrip, 2010)
;
_computing_structure_refinement
;
GSAS/Expgui (Larsen & Von Dreele, 2000: Toby, 2001)
;
_computing_structure_solution    n/a
_diffrn_ambient_temperature      295
_diffrn_measurement_device_type  'HRPD, High resolution neutron powder'
_diffrn_radiation_type           neutron
_exptl_absorpt_coefficient_mu    '0.0284 + 0.0033 * \l'
_exptl_absorpt_correction_T_max  0.6995
_exptl_absorpt_correction_T_min  0.6030
_exptl_absorpt_correction_type   analytical
_exptl_absorpt_process_details
;
Data were corrected for self shielding using \s~scatt~ = 94.190 barns and
 \s~ab~(\l) = 19.484 barns at 1.798 \%A during the normalisation procedure.
The linear absorption coefficient is wavelength dependent and is calculated as:
          \m = 0.0284 + 0.0033 * \l  [mm^-1^]
;
_exptl_crystal_density_diffrn    3.5615
_exptl_crystal_density_method    'not measured'
_pd_block_id                     2015-05-09T19:22|NA2WO4_2D2O|Fortes|HRPD
_pd_calc_method                  'Rietveld Refinement'
_pd_char_colour                  white
_pd_instr_dist_spec/detc         965
_pd_instr_dist_src/spec          95000
_pd_instr_location
;
High Resolution Powder Diffractometer, ISIS neutron spallation source,
 Rutherford Appleton Laboratory, Oxfordshire, U.K.
;
_pd_meas_2theta_fixed            168.329
_pd_meas_number_of_points        4610
_pd_meas_scan_method             tof
_pd_phase_name                   Na2WO4.2D2O
_pd_prep_pressure                100
_pd_prep_temperature             323
_pd_proc_info_data_reduction
;
Both the mass and the volume of the specimen were measured in order to compute
 the packing number density (3.02 mol nm^-3^). The stoichiometry of the compound
 was used to calculate the scattering and absorption cross sections (94.190 and
 19.484 barns at \l = 1.798 \%A, respectively) from data tabulated by
 NIST (http://www.ncnr.nist.gov/resources/n-lengths/).
 Together, these data were used by the Mantid normalisation routine to apply
 the appropriate self shielding correction to the data.
This Mantid routine focuses the data to a common scattering angle and
 normalises the data with respect to the incident neutron spectrum by reference
 to a V:Nb null-scattering rod.
;
_pd_proc_info_excluded_regions
;
none
;
_pd_proc_ls_background_function
;   GSAS Background function number 1 with 12 terms.
 Shifted Chebyshev function of 1st kind
1: 3.91163, 2: 1.22805, 3: -0.206144, 4: -8.53351x10^-2^,
 5: -9.966470x10^-2^, 6: -1.847470x10^-2^, 7: -1.38195x10^-2^,
 8: 9.956170x10^-4^, 9: 4.49839x10^-3^, 10: -2.199010x10^-2^,
11: 2.57524x10^-2^, 12: -2.00574x10^-3^
;
_pd_proc_ls_peak_cutoff          0.00100
_pd_proc_ls_profile_function
;
TOF profile function #3 (21 terms).
Profile coefficients for exp pseudovoigt
convolution [Von Dreele, 1990 (unpublished)]
(\a) = 0.1414, (\b~0~) = 0.026250, (\b~1~) = 0.004690,
(\s~0~) = 0, (\s~1~) = 322.9, (\s~2~) = 15.7,
(\g~0~) = 0, (\g~1~) = 0, (\g~2~) = 0,
(\g~2s~) = 0, (\g~1e~) = 0, (\g~2e~) = 0,
(\e~i~) = 0, (\e~a~) = 0, (\e~A~) = 0,
(\g~11~) = 0.023, (\g~22~) = 0, (\g~33~) = 0.006,
(\g~12~) = 0.050, (\g~13~) = 0.016, (\g~23~) = 0.017.
Peak tails ignored  where intensity <0.0010x peak.
Aniso. broadening axis   0.0   0.0   1.0
;
_pd_proc_ls_prof_R_factor        0.0139
_pd_proc_ls_prof_wR_expected     0.0074
_pd_proc_ls_prof_wR_factor       0.0132
_pd_proc_number_of_points        4610
_pd_spec_mounting                'vanadium tube'
_pd_spec_mount_mode              transmission
_pd_spec_shape                   cylinder
_pd_spec_size_axial              50
_pd_spec_size_equat              11
_refine_ls_goodness_of_fit_all   1.82
_refine_ls_matrix_type           full
_refine_ls_number_constraints    0
_refine_ls_number_parameters     133
_refine_ls_number_restraints     0
_refine_ls_shift/su_max          0.04
_refine_ls_shift/su_mean         0.00
_reflns_number_total             2338
_cod_data_source_file            wm5172sup1.cf
_cod_data_source_block           Na2WO4.2D2O
_cod_original_cell_volume        1245.324(3)
_cod_database_code               2240858