data_2102123
_publ_section_title
;
 Structures and phase transitions of B-Ta₂O₅ and
 Z-Ta₂O₅: two high-pressure forms of Ta₂O₅
;
_journal_issue                   4
_journal_name_full               'Acta Crystallographica Section B'
_journal_page_first              659
_journal_page_last               665
_journal_paper_doi               10.1107/S0108768100005462
_journal_volume                  56
_journal_year                    2000
_chemical_formula_iupac          'Ta2 O5'
_chemical_formula_moiety         'O5 Ta2'
_chemical_formula_structural     'Ta2 O5'
_chemical_formula_sum            'O5 Ta2'
_chemical_formula_weight         441.89
_chemical_name_common            B-Ta2O5
_chemical_name_systematic
;
ditantalum penta oxide
;
_space_group_IT_number           15
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-C 2yc'
_symmetry_space_group_name_H-M   'C 1 2/c 1'
_cell_angle_alpha                90.0
_cell_angle_beta                 104.264(2)
_cell_angle_gamma                90.0
_cell_formula_units_Z            4
_cell_length_a                   12.7853(4)
_cell_length_b                   4.85370(10)
_cell_length_c                   5.5276(2)
_cell_measurement_temperature    293
_cell_volume                     332.446(18)
_computing_cell_refinement       'DBW 3.2 S Wiles et al.,1988)'
_computing_data_collection       'Stoe Stadi/P, Powdat'
_computing_data_reduction        'Stoe Stadi/P, Rawdat'
_computing_structure_refinement  'DBW 3.2 S Wiles et al.,1988)'
_diffrn_ambient_temperature      293
_diffrn_measurement_device_type  'Stoe PSD'
_diffrn_radiation_monochromator  Ge
_diffrn_radiation_type           CuK\a~1~
_diffrn_radiation_wavelength     1.54056
_exptl_crystal_density_diffrn    8.83
_exptl_crystal_density_method    'not measured'
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_all   1.07
_refine_ls_hydrogen_treatment    none
_refine_ls_matrix_type           fsqd
_refine_ls_number_parameters     47
_refine_ls_shift/su_max          .2
_refine_ls_structure_factor_coef Inet
_refine_ls_weighting_details     'w = 1/Yi'
_refine_ls_weighting_scheme      calc
_[local]_cod_data_source_file    os0050.cif
_[local]_cod_data_source_block   B
_[local]_cod_cif_authors_sg_H-M  'C 2/c'
_cod_depositor_comments
;
Luca 25/2/2014
Corrected the occupancies

The following automatic conversions were performed:

'_refine_ls_weighting_scheme' value '1/Y~i~' was changed to 'calc'.
New tag '_refine_ls_weighting_details' was created. The value of the
new tag was set to 'w = 1/Y~i~'.

Automatic conversion script
Id: cif_fix_values 3143 2015-03-26 13:38:13Z robertas 
;
_cod_original_cell_volume        332.45
_cod_database_code               2102123
loop_
_symmetry_equiv_pos_site_id
_symmetry_equiv_pos_as_xyz
1 x,y,z
2 -x,y,1/2-z
3 -x,-y,-z
4 x,-y,1/2+z
5 1/2+x,1/2+y,z
6 1/2-x,1/2+y,1/2-z
7 1/2-x,1/2-y,-z
8 1/2+x,1/2-y,1/2+z
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_U_iso_or_equiv
_atom_site_thermal_displace_type
_atom_site_occupancy_[sic]
_atom_site_type_symbol
_atom_site_occupancy
Ta .13950(10) .2470(15) .2623(2) 1.10(3) Uiso 8 Ta 1
O1 0 .102(4) .25 1.8(2) Uiso 4 O 1
O2 .389(2) .051(2) .990(4) 1.8(2) Uiso 8 O 1
O3 .2990(10) .431(3) .355(3) 1.8(2) Uiso 8 O 1
loop_
_atom_type_symbol
_atom_type_description
_atom_type_scat_dispersion_real
_atom_type_scat_dispersion_imag
_atom_type_scat_source
Ta Ta -6.351 5.271 'International Tables for Crystallography (Vol. IV)'
O O .047 .032 'International Tables for Crystallography (Vol. IV)'
loop_
_geom_bond_atom_site_label_1
_geom_bond_atom_site_label_2
_geom_bond_site_symmetry_2
_geom_bond_distance
_geom_bond_publ_flag
Ta Ta 7_556 3.351(5) yes
Ta Ta 2_555 3.536(6) yes
Ta O1 . 1.90(2) yes
Ta O2 6_556 2.10(5) yes
Ta O2 7_556 1.67(6) yes
Ta O3 . 2.17(5) yes
Ta O3 7_556 2.24(5) yes
Ta O3 6_545 1.91(5) yes
O1 O1 3_555 2.94(3) yes
O1 O2 6_556 2.80(6) yes
O1 O2 7_556 2.75(6) yes
O1 O3 7_556 2.94(5) yes
O1 O3 6_545 2.89(5) yes
O2 O2 3_657 2.86(9) yes
O2 O2 4_555 2.81(9) yes
O2 O3 6_546 2.80(8) yes
O2 O3 4_555 2.63(6) yes
O2 O3 7_556 2.68(8) yes
O2 O3 4_565 2.79(6) yes
O3 O3 7_556 2.87(7) yes
O3 O3 4_565 2.84(7) yes
O3 O3 6_545 2.84(6) yes
