#\#CIF_2.0
# Created by the Bilbao Crystallographic Server
# http://www.cryst.ehu.es
# Date: 04/02/2026

data_5yOhtAoR
_audit_creation_date            2026-04-02
_audit_creation_method          "Bilbao Crystallographic Server"

_chemical_name_systematic
;
;
_chemical_name_common                    ?
_chemical_formula_moiety                 ?
_chemical_formula_structural             ?
_chemical_formula_analytical             ?
_chemical_formula_iupac                  ?
_chemical_formula_sum                    "Fe4 Nb2 O9"
_chemical_formula_weight                 ?
_chemical_melting_point                  ?
_chemical_compound_source                ?
_chemical_absolute_configuration         ?


_citation_journal_abbrev        "PHYSICAL REVIEW B"
_citation_journal_volume        112
_citation_page_first            .
_citation_page_last             .
_citation_article_id            134439
_citation_year                  2025
_citation_DOI                   10.1103/9tgw-l1nj

loop_
_citation_author_name
"Raktim Datta"
"Kapil Kumar"
"Dong Gun Oh"
"Dongwook Kim"
"Rahul Goel"
"Nara Lee"
"Ara Go"
"Young Jai Choi"
"Valery Kiryukhin"
"Sungkyun Choi"

_temperature_position_structure         40
_temperature_atom_positions             .
_temperature_non-magn_atom_positions    .
_temperature_cell_parameters            1.5

_atomic_positions_source_database_code_ICSD  32330
_atomic_positions_source_other               .

_transition_temperature     87.5
_experiment_temperature     1.5

loop_
_irrep_id
_irrep_dimension
_irrep_small_dimension
_irrep_direction_type
_irrep_action
_irrep_modes_number
_irrep_presence
mGM1- 1 1 . primary 6 .
MGM2- 1 1 . primary 6 .

_exptl_crystal_magnetic_properties_details
;
NPD
Only positions of Fe sites are given. For the rest, here a model at 40K retrieved from the ICSD is used.
This is one of two models reported and considered more probable. This is the one proposed by the authors, to be consistent with magnetoelectric properties. For the second one with higher symmetry and much fewer free paramters see #0.1143.
Standard deviations of the spins in the paper with three digits have been here reduced to a single one
;

_active_magnetic_irreps_details
;
1k magnetic structure
Two 1-dim irreps involved as primary
;

_parent_space_group.name_H-M_alt  'C 2/c'
_parent_space_group.IT_number                       15
_parent_space_group.transform_Pp_abc  'a,b,c;0,0,0'

loop_
_parent_propagation_vector.id
_parent_propagation_vector.kxkykz
k1 [0 0 0]

_parent_space_group.child_transform_Pp_abc  'a,b,c;0,0,0'
_space_group_magn.transform_BNS_Pp_abc  '1/2a+1/2b,-1/2a+1/2b,c;0,0,0'


_space_group_magn.number_BNS  2.6
_space_group_magn.name_BNS  "P -1'"
_space_group_magn.point_group_name  "-1'"
_space_group_magn.point_group_number  "2.3.5"
_cell_length_a                 9.08610
_cell_length_b                 5.19700
_cell_length_c                 14.23400
_cell_angle_alpha              90.00
_cell_angle_beta               91.29
_cell_angle_gamma              90.00

loop_
_space_group_symop_magn_operation.id
_space_group_symop_magn_operation.xyz
1 x,y,z,+1 
2 -x,-y,-z,-1 

loop_
_space_group_symop_magn_centering.id
_space_group_symop_magn_centering.xyz
1 x,y,z,+1 
2 x+1/2,y+1/2,z,+1 

loop_
_atom_site_label
_atom_site_type_symbol
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
Nb1_1 Nb 0.00100 0.99960 0.64284 1
Nb1_2 Nb 0.99900 0.99960 0.85716 1
Fe1_1 Fe 0.8320(4) 0.4948(7) 0.6887(2) 1
Fe1_2 Fe 0.1706(3) 0.5028(7) 0.8070(2) 1
Fe2_1 Fe 0.8337(3) 0.4915(7) 0.4840(2) 1
Fe2_2 Fe 0.1647(3) 0.5094(6) 0.0143(2) 1
O1_1 O 0.84500 0.82100 0.08630 1
O1_2 O 0.15500 0.82100 0.41370 1
O2_1 O 0.67200 0.35500 0.08580 1
O2_2 O 0.32800 0.35500 0.41420 1
O3_1 O 0.98600 0.32800 0.08330 1
O3_2 O 0.01400 0.32800 0.41670 1
O4 O 0.00000 0.72200 0.25000 1
O5_1 O 0.14100 0.14500 0.25000 1
O5_2 O 0.85900 0.14500 0.25000 1

loop_
_atom_site_moment.label
_atom_site_moment.crystalaxis_x
_atom_site_moment.crystalaxis_y
_atom_site_moment.crystalaxis_z
_atom_site_moment.symmform
_atom_site_moment.magnitude
_atom_site_moment.spherical_azimuthal
_atom_site_moment.spherical_polar
Fe1_1 3.57(2) 1.1(1) -0.86(4)  mx,my,mz 3.8(1) ? ?
Fe1_2 -3.21(2) -1.1(1) 1.48(4) mx,my,mz 3.7(1) ? ?
Fe2_1  4.37(3)  0.0(1) -1.94(4) mx,my,mz 4.8(1) ? ?
Fe2_2 -5.43(3)  0.0(1) 1.87(3) mx,my,mz 5.8(1) ? ?

