FeNiP2O9

High-Entropy Materials HEA

MP-ID: mp-1043619 · Space group: Pnma (#62)

Materials Project API

Basic Information

Formula

FeNiP2O9

MP-ID

mp-1043619

Elements

Sites

Density

3.0896

g/cm³

Volume

688.98

Å³

Cell a

6.3172

Cell b

7.7398

Cell c

14.0912

α Angle

90.00

β Angle

90.00

γ Angle

90.00

Space Group

Pnma

Point Group

mmm

Crystal System

Orthorhombic

Bravais Lattice

Stability

Packing Fraction

X-ray Diffraction

Diffraction Pattern

Target / Radiation

X-axis: 2θ (°); Y-axis: relative intensity; Cu Kα ; λ=1.5418 Å

Diffraction Peaks (Top 24)

2θ	d (Å)	I	hkl
12.56	7.0456	100.0	(0,0,2)
13.05	6.7839	35.3	(0,1,1)
17.02	5.2102	71.9	(0,1,2)
18.13	4.8940	33.8	(1,1,0)
19.20	4.6231	65.2	(1,1,1)
22.12	4.0195	39.0	(1,1,2)
22.14	4.0155	25.2	(0,1,3)
22.98	3.8699	10.3	(0,2,0)
23.84	3.7317	77.5	(0,2,1)
26.27	3.3919	17.8	(0,2,2)
26.30	3.3888	1.8	(1,1,3)
27.77	3.2130	3.3	(1,2,1)
27.82	3.2063	24.4	(0,1,4)
28.25	3.1586	16.8	(2,0,0)
29.02	3.0767	1.3	(1,0,4)
29.90	2.9884	1.2	(1,2,2)
29.92	2.9868	33.5	(0,2,3)
31.03	2.8822	6.8	(2,0,2)
31.24	2.8635	67.2	(2,1,1)
31.29	2.8591	10.9	(1,1,4)
33.17	2.7010	19.4	(2,1,2)
33.85	2.6481	28.4	(0,1,5)
34.43	2.6051	17.9	(0,2,4)
35.37	2.5378	20.6	(0,3,1)

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Energy Properties

Formation Energy/atom

-1.83230

eV/atom

Energy/atom

-7.18712

eV/atom

Energy above Hull

0.1959

eV/atom

Uncorrected Energy

-6.3425

eV/atom

Volume/atom

13.25

Å³

c/a Ratio

2.2306

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

24.0021

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.034840

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

O · 0.692

Element Family

Metalloid-Nonmetal

Solute Fraction

0.308

Interstitial Fraction

0.154

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

0.9372

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

7.7915

J/mol·K

Ω Parameter

0.8441

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

34.579%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.6570

smaller = more stable mixing

VEC

4.923

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-3.314

kJ/mol; negative = exothermic mixing

Entropy Norm

0.6760

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (1)

aaaegdmb

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-1043619

Reference Citation

The crystal structure and related material properties of FeNiP2O9 were obtained from the Materials Project database (MP-ID: mp-1043619, 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_FeNiP2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.31723900
_cell_length_b   7.73982400
_cell_length_c   14.09115500
_cell_angle_alpha   90.00000000
_cell_angle_beta   90.00000000
_cell_angle_gamma   90.00000000
_symmetry_Int_Tables_number   1
_chemical_formula_structural   FeNiP2O9
_chemical_formula_sum   'Fe4 Ni4 P8 O36'
_cell_volume   688.97741392
_cell_formula_units_Z   4
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  0.75000000  0.84564500  0.38096900  1.0
  Fe  Fe1  1  0.25000000  0.15435500  0.61903100  1.0
  Fe  Fe2  1  0.25000000  0.34564500  0.11903100  1.0
  Fe  Fe3  1  0.75000000  0.65435500  0.88096900  1.0
  Ni  Ni4  1  0.50000000  0.50000000  0.50000000  1.0
  Ni  Ni5  1  0.50000000  0.00000000  0.00000000  1.0
  Ni  Ni6  1  0.00000000  0.00000000  0.00000000  1.0
  Ni  Ni7  1  0.00000000  0.50000000  0.50000000  1.0
  P  P8  1  0.25000000  0.84954000  0.43846700  1.0
  P  P9  1  0.75000000  0.15046000  0.56153300  1.0
  P  P10  1  0.75000000  0.34954000  0.06153300  1.0
  P  P11  1  0.25000000  0.65046000  0.93846700  1.0
  P  P12  1  0.75000000  0.89038500  0.18775200  1.0
  P  P13  1  0.25000000  0.10961500  0.81224800  1.0
  P  P14  1  0.25000000  0.39038500  0.31224800  1.0
  P  P15  1  0.75000000  0.60961500  0.68775200  1.0
  O  O16  1  0.04613900  0.09805100  0.87203600  1.0
  O  O17  1  0.54613900  0.90194900  0.12796400  1.0
  O  O18  1  0.95386100  0.59805100  0.62796400  1.0
  O  O19  1  0.45386100  0.40194900  0.37203600  1.0
  O  O20  1  0.95386100  0.90194900  0.12796400  1.0
  O  O21  1  0.45386100  0.09805100  0.87203600  1.0
  O  O22  1  0.04613900  0.40194900  0.37203600  1.0
  O  O23  1  0.54613900  0.59805100  0.62796400  1.0
  O  O24  1  0.25000000  0.83846900  0.97976700  1.0
  O  O25  1  0.75000000  0.16153100  0.02023300  1.0
  O  O26  1  0.75000000  0.33846900  0.52023300  1.0
  O  O27  1  0.25000000  0.66153100  0.47976700  1.0
  O  O28  1  0.75000000  0.64076000  0.45354400  1.0
  O  O29  1  0.25000000  0.35924000  0.54645600  1.0
  O  O30  1  0.25000000  0.14076000  0.04645600  1.0
  O  O31  1  0.75000000  0.85924000  0.95354400  1.0
  O  O32  1  0.75000000  0.72298300  0.24863900  1.0
  O  O33  1  0.25000000  0.27701700  0.75136100  1.0
  O  O34  1  0.25000000  0.22298300  0.25136100  1.0
  O  O35  1  0.75000000  0.77701700  0.74863900  1.0
  O  O36  1  0.44369100  0.63430500  0.87324700  1.0
  O  O37  1  0.94369100  0.36569500  0.12675300  1.0
  O  O38  1  0.55630900  0.13430500  0.62675300  1.0
  O  O39  1  0.05630900  0.86569500  0.37324700  1.0
  O  O40  1  0.55630900  0.36569500  0.12675300  1.0
  O  O41  1  0.05630900  0.63430500  0.87324700  1.0
  O  O42  1  0.44369100  0.86569500  0.37324700  1.0
  O  O43  1  0.94369100  0.13430500  0.62675300  1.0
  O  O44  1  0.75000000  0.47084100  0.76808200  1.0
  O  O45  1  0.25000000  0.52915900  0.23191800  1.0
  O  O46  1  0.25000000  0.97084100  0.73191800  1.0
  O  O47  1  0.75000000  0.02915900  0.26808200  1.0
  O  O48  1  0.75000000  0.48201200  0.98229600  1.0
  O  O49  1  0.25000000  0.51798800  0.01770400  1.0
  O  O50  1  0.25000000  0.98201200  0.51770400  1.0
  O  O51  1  0.75000000  0.01798800  0.48229600  1.0

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