#------------------------------------------------------------------------------
#$Date: 2009-12-10 18:47:15 +0200 (Thu, 10 Dec 2009) $
#$Revision: 936 $
#$URL: file:///home/coder/svn-repositories/cod/cif/1/1100917.cif $
#------------------------------------------------------------------------------
#
# This file is available in the Crystallography Open Database (COD),
# http://www.crystallography.net/
#
# All data on this site have been placed in the public domain by the
# contributors.
#
data_1100917
_journal_name_full               'Acta Crystallographica, Section C'
_journal_year                    2000
_journal_volume                  56
_journal_page_first              916
_journal_page_last               918
_publ_section_title
;
Structural study of AgNbO~3~ at room temperature
;
loop_
_publ_author_name
'Fabry, Jan'
'Zikmund, Zdenek'
'Kania, Antoni'
'Petricek, Vaclav'
_publ_section_synopsis
;
AgNbO~3~ is a tilted perovskite which is isostructural with NaNbO~3~ at room
temperature.
;
_chemical_name_systematic
;
silver niobate
;
_chemical_formula_moiety         'Ag Nb O3'
_chemical_formula_sum            'Ag Nb O3'
_chemical_formula_structural     'Ag Nb O3'
_chemical_formula_iupac          'Ag Nb O3'
_chemical_formula_weight         248.77
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_H-M   'P b c m'
_cell_length_a                   5.5462(3)
_cell_length_b                   5.6028(4)
_cell_length_c                   15.6365(13)
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_volume                     485.90(6)
_cell_formula_units_Z            8
_cell_measurement_reflns_used    50
_cell_measurement_theta_min      5
_cell_measurement_theta_max      33
_cell_measurement_temperature    292.0(10)
_exptl_crystal_description       prism
_exptl_crystal_colour            'light brown'
_exptl_crystal_size_max          .31
_exptl_crystal_size_mid          .17
_exptl_crystal_size_min          .09
_exptl_crystal_density_diffrn    6.799
_exptl_crystal_density_meas      'not measured'
_exptl_crystal_density_method    ?
_exptl_crystal_F_000             896
_exptl_absorpt_coefficient_mu    12.492
_exptl_absorpt_correction_type   Gaussian
_exptl_absorpt_process_details   '(Templeton & Templeton, 1978)'
_exptl_absorpt_correction_T_min  .130
_exptl_absorpt_correction_T_max  .356
_diffrn_radiation_type           'Mo K\a'
_diffrn_radiation_wavelength     .71073
_diffrn_measurement_device       'Hilger & Watts'
_diffrn_measurement_method       \w/2\q
_diffrn_reflns_number            5156
_diffrn_reflns_av_R_equivalents  .025
_diffrn_reflns_theta_max         30
_diffrn_reflns_theta_full        30
_diffrn_reflns_limit_h_min       -7
_diffrn_reflns_limit_h_max       7
_diffrn_reflns_limit_k_min       -7
_diffrn_reflns_limit_k_max       7
_diffrn_reflns_limit_l_min       -21
_diffrn_reflns_limit_l_max       22
_diffrn_standards_number         3
_diffrn_standards_interval_count 30
_diffrn_standards_interval_time  ?
_diffrn_standards_decay_%        7.0
_reflns_number_total             1689
_reflns_number_gt                1497
_reflns_threshold_expression     I>3\s(I)
_refine_ls_structure_factor_coef F
_refine_ls_matrix_type           fullcycle
_refine_ls_R_factor_gt           .034
_refine_ls_wR_factor_ref         .053
_refine_ls_goodness_of_fit_all   2.69
_refine_ls_goodness_of_fit_ref   2.84
_refine_ls_number_reflns         1689
_refine_ls_number_parameters     52
_refine_ls_number_constraints    0
_refine_ls_hydrogen_treatment    none
_refine_ls_weighting_scheme      'w = (\s^2^(F~o~)+0.0001(F~o~)^2^)^-1^'
_refine_ls_shift/su_max          .01
_refine_diff_density_max         1.20
_refine_diff_density_min         -3.65
_refine_ls_extinction_method     'type II (Becker & Coppens, 1974)'
_refine_ls_extinction_coef       .000228(4)
loop_
_symmetry_equiv_pos_as_xyz
'x, y, z'
'x, y, -z+1/2'
'-x, y+1/2, z'
'-x, y+1/2, -z+1/2'
'-x, -y, -z'
'-x, -y, z+1/2'
'x, -y+1/2, -z'
'x, -y+1/2, z+1/2'
loop_
_atom_type_symbol
_atom_type_scat_dispersion_real
_atom_type_scat_dispersion_imag
_atom_type_scat_source
Ag -.897 1.102 International_Tables_vol_IV_Table_2.2A_and_2.3.1
Nb -2.073 .622 International_Tables_vol_IV_Table_2.2A_and_2.3.1
O .011 .006 International_Tables_vol_IV_Table_2.2A_and_2.3.1
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_U_iso_or_equiv
_atom_site_adp_type
_atom_site_occupancy
_atom_site_type_symbol
Ag1 .75770(3) 0.22738(7) 0.75 .01280(10) Uani 1 Ag
Ag2 .75550(3) 0.25 0.5 .01280(10) Uani 1 Ag
Nb .74525(2) 0.72338(7) 0.625014(8) .00590(10) Uani 1 Nb
O1 .6978(2) 0.7664(2) 0.75 .0090(4) Uani 1 O
O2 .8043(2) 0.75 0.5 .0095(4) Uani 1 O
O3 .4662(2) 0.5364(2) 0.61132(6) .0088(3) Uani 1 O
O4 -.0334(2) 0.4727(2) 0.63865(7) .0092(3) Uani 1 O
loop_
_atom_site_aniso_label
_atom_site_aniso_U_11
_atom_site_aniso_U_22
_atom_site_aniso_U_33
_atom_site_aniso_U_12
_atom_site_aniso_U_13
_atom_site_aniso_U_23
_atom_site_aniso_type_symbol
Ag1 .0128(2) .0123(2) .0133(2) -.00211(4) .0000 .0000 Ag
Ag2 .0113(2) .01410(10) .0130(2) .0000 .0000 .00107(7) Ag
Nb .0051(2) .0040(2) .0085(2) -.00014(3) -.00061(4) .00031(4) Nb
O1 .0118(6) .0119(7) .0031(7) .0009(4) .0000 .0000 O
O2 .0100(6) .0127(6) .0059(7) .0000 .0000 .0004(4) O
O3 .0064(4) .0084(5) .0115(5) -.0033(3) -.0013(3) .0014(3) O
O4 .0086(4) .0077(5) .0114(5) .0030(3) .0010(3) .0013(3) O