Basic Information
Formula
Fe(NiO2)2
MP-ID
mp-640147
Elements
3
Sites
14
Density
5.7357
g/cm³
Volume
137.36
ų
Cell a
5.7913
Å
Cell b
5.7917
Å
Cell c
5.7915
Å
α Angle
60.00
°
β Angle
60.00
°
γ Angle
60.00
°
Space Group
Fd-3m
Point Group
m-3m
Crystal System
Cubic
Bravais Lattice
cF
Stability
No
Packing Fraction
0.7405
X-ray Diffraction
Diffraction Pattern
X-axis: 2θ (°); Y-axis: relative intensity; Cu Kα ; λ=1.5418 Å
Diffraction Peaks (Top 24)
| 2θ | d (Å) | I | hkl |
|---|---|---|---|
| 18.77 | 4.7289 | 41.0 | (0,1,0) |
| 18.77 | 4.7288 | 41.1 | (0,0,1) |
| 18.77 | 4.7288 | 41.0 | (1,1,1) |
| 18.77 | 4.7286 | 41.1 | (1,0,0) |
| 30.88 | 2.8958 | 51.2 | (1,2,1) |
| 30.88 | 2.8958 | 51.2 | (0,1,-1) |
| 30.88 | 2.8958 | 51.2 | (1,1,2) |
| 30.88 | 2.8957 | 51.2 | (1,0,-1) |
| 30.88 | 2.8957 | 51.2 | (1,-1,0) |
| 30.88 | 2.8957 | 51.2 | (2,1,1) |
| 36.38 | 2.4696 | 100.0 | (1,2,0) |
| 36.38 | 2.4695 | 100.0 | (1,2,2) |
| 36.38 | 2.4695 | 100.0 | (0,2,1) |
| 36.38 | 2.4695 | 100.0 | (1,1,-1) |
| 36.38 | 2.4695 | 99.9 | (2,2,1) |
| 36.38 | 2.4695 | 100.0 | (1,0,2) |
| 36.38 | 2.4695 | 100.0 | (0,1,2) |
| 36.38 | 2.4695 | 100.0 | (1,-1,1) |
| 36.38 | 2.4695 | 100.0 | (2,1,2) |
| 36.38 | 2.4695 | 100.0 | (1,-1,-1) |
| 36.38 | 2.4695 | 100.0 | (2,1,0) |
| 36.38 | 2.4694 | 100.0 | (2,0,1) |
| 38.06 | 2.3644 | 35.1 | (0,2,0) |
| 38.06 | 2.3644 | 35.1 | (0,0,2) |
Energy Properties
Formation Energy/atom
-1.30865
eV/atom
Energy/atom
-6.99752
eV/atom
Energy above Hull
0.0103
eV/atom
Uncorrected Energy
-10.2779
eV/atom
Volume/atom
9.81
ų
c/a Ratio
1.0000
Electronic Properties
Metallic
Metal
Band Gap
0
eV
Direct Gap
No
CBM
N/A
eV
Magnetic Properties
Magnetic
Yes
Total Mag. Moment
3.9948
μB
Mag. Ordering
FiM
Mag. Sites
6
Magnetization/Volume
0.029080
μB/ų
Elastic Properties
Elastic data not available
Feature Analysis
Element Composition (atomic fraction)
Composition Info
Major / Matrix Element
O · 0.571
Element Family
Metalloid-Nonmetal
Solute Fraction
0.429
Interstitial Fraction
0.000
Composite Radar (normalized)
Element-Class Share
Mix Entropy ΔS/R
0.9557
HEA criterion (>1.0 = high entropy)
Mix Entropy ΔS
7.9457
J/mol·K
Ω Parameter
19.0713
Ω > 1.1 favors solid solution
Atomic Size Mismatch δr
36.491%
δr < 6.6% favors single-phase solid solution
Electronegativity Diff Δχ
0.7707
smaller = more stable mixing
VEC
6.286
valence electron concentration, affects phase stability
Mix Enthalpy ΔH_mix
-0.327
kJ/mol; negative = exothermic mixing
Entropy Norm
0.8699
SS Former
0
Phase Tendency
IM
Related Tasks
Citation & References
Materials Project Page
https://materialsproject.org/materials/mp-640147
Reference Citation
The crystal structure and related material properties of Fe(NiO2)2 were obtained from the Materials Project database (MP-ID: mp-640147, database version v2026.04.13).
Literature Citation
Horton, M.K., Huck, P., Yang, R.X. et al. Accelerated data-driven materials science with the Materials Project. Nat. Mater. 24, 1522–1532 (2025). https://doi.org/10.1038/s41563-025-02272-0
3D Crystal Structure Rendering
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Raw CIF Data
# generated using pymatgen
data_Fe(NiO2)2
_symmetry_space_group_name_H-M 'P 1'
_cell_length_a 5.79134102
_cell_length_b 5.79167446
_cell_length_c 5.79152306
_cell_angle_alpha 60.00032881
_cell_angle_beta 59.99990327
_cell_angle_gamma 59.99888030
_symmetry_Int_Tables_number 1
_chemical_formula_structural Fe(NiO2)2
_chemical_formula_sum 'Fe2 Ni4 O8'
_cell_volume 137.35932891
_cell_formula_units_Z 2
loop_
_symmetry_equiv_pos_site_id
_symmetry_equiv_pos_as_xyz
1 'x, y, z'
loop_
_atom_site_type_symbol
_atom_site_label
_atom_site_symmetry_multiplicity
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
Fe Fe0 1 0.12501756 0.12500167 0.12498021 1.0
Fe Fe1 1 0.87498356 0.87499823 0.87501878 1.0
Ni Ni2 1 0.50000507 0.50000716 0.99999313 1.0
Ni Ni3 1 0.00000492 0.50000721 0.49999357 1.0
Ni Ni4 1 0.50000323 0.00000826 0.49999408 1.0
Ni Ni5 1 0.50000476 0.50000713 0.49999462 1.0
O O6 1 0.27573937 0.74145001 0.74136849 1.0
O O7 1 0.25858471 0.72436340 0.25855251 1.0
O O8 1 0.72425384 0.25854331 0.25863847 1.0
O O9 1 0.25858736 0.25848552 0.25855325 1.0
O O10 1 0.25865296 0.25853280 0.72426525 1.0
O O11 1 0.74141016 0.27562967 0.74145332 1.0
O O12 1 0.74134170 0.74145871 0.27574280 1.0
O O13 1 0.74140881 0.74150592 0.74145252 1.0
