Fe3CoNi2(PO4)6

High-Entropy Materials HEA

MP-ID: mp-770497 · Space group: R3 (#146)

Materials Project API

Basic Information

Formula

Fe3CoNi2(PO4)6

MP-ID

mp-770497

Elements

Sites

Density

3.4966

g/cm³

Volume

433.91

Å³

Cell a

8.4332

Cell b

8.4332

Cell c

8.4332

α Angle

61.03

β Angle

61.03

γ Angle

61.03

Space Group

Point Group

Crystal System

Trigonal

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
14.74	6.0081	3.8	(1,1,0)
20.74	4.2819	100.0	(1,0,-1)
21.07	4.2156	10.3	(2,1,1)
24.54	3.6282	98.8	(2,1,0)
25.55	3.4870	19.2	(2,0,0)
29.74	3.0041	5.7	(2,0,2)
29.74	3.0041	2.9	(2,2,0)
32.23	2.7773	15.8	(2,0,-1)
33.13	2.7038	4.4	(2,-1,1)
33.13	2.7038	2.2	(2,1,-1)
33.56	2.6703	74.9	(3,2,1)
36.34	2.4722	44.0	(2,-1,-1)
36.54	2.4592	3.1	(3,1,0)
37.13	2.4215	2.3	(3,3,2)
38.92	2.3139	1.7	(3,2,0)
42.21	2.1410	2.4	(2,0,-2)
42.91	2.1078	11.7	(4,2,2)
44.34	2.0430	1.6	(3,1,-1)
44.76	2.0248	1.3	(4,2,1)
45.09	2.0106	4.3	(4,3,2)
45.28	2.0027	6.3	(3,0,3)
48.12	1.8911	35.9	(4,3,1)
49.58	1.8385	4.9	(4,1,0)
49.99	1.8245	1.4	(2,2,-2)

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Energy Properties

Formation Energy/atom

-2.14521

eV/atom

Energy/atom

-7.57154

eV/atom

Energy above Hull

0.0650

eV/atom

Uncorrected Energy

-6.7389

eV/atom

Volume/atom

12.05

Å³

c/a Ratio

1.0000

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

21.6063

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.049790

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

O · 0.667

Element Family

Metalloid-Nonmetal

Solute Fraction

0.333

Interstitial Fraction

0.167

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.0361

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

8.6144

J/mol·K

Ω Parameter

1.0630

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

34.723%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.6726

smaller = more stable mixing

VEC

4.972

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-3.124

kJ/mol; negative = exothermic mixing

Entropy Norm

0.6438

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (2)

aaabzgdg aaaczbld

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-770497

Reference Citation

The crystal structure and related material properties of Fe3CoNi2(PO4)6 were obtained from the Materials Project database (MP-ID: mp-770497, 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_Fe3CoNi2(PO4)6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.43322428
_cell_length_b   8.43322428
_cell_length_c   8.43322435
_cell_angle_alpha   61.02737787
_cell_angle_beta   61.02737787
_cell_angle_gamma   61.02738154
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Fe3CoNi2(PO4)6
_chemical_formula_sum   'Fe3 Co1 Ni2 P6 O24'
_cell_volume   433.91021241
_cell_formula_units_Z   1
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  0.14287100  0.14287100  0.14287100  1.0
  Fe  Fe1  1  0.35600100  0.35600100  0.35600100  1.0
  Fe  Fe2  1  0.64305100  0.64305100  0.64305100  1.0
  Co  Co3  1  0.85830800  0.85830800  0.85830800  1.0
  Ni  Ni4  1  0.00023400  0.00023400  0.00023400  1.0
  Ni  Ni5  1  0.50044300  0.50044300  0.50044300  1.0
  P  P6  1  0.75055600  0.04215000  0.45878000  1.0
  P  P7  1  0.04215000  0.45878000  0.75055600  1.0
  P  P8  1  0.45878000  0.75055600  0.04215000  1.0
  P  P9  1  0.54596900  0.24735800  0.95117900  1.0
  P  P10  1  0.95117900  0.54596900  0.24735800  1.0
  P  P11  1  0.24735800  0.95117900  0.54596900  1.0
  O  O12  1  0.31148400  0.10929800  0.51163300  1.0
  O  O13  1  0.51163300  0.31148400  0.10929800  1.0
  O  O14  1  0.90915500  0.05714100  0.25969700  1.0
  O  O15  1  0.10929800  0.51163300  0.31148400  1.0
  O  O16  1  0.81987800  0.00469800  0.61900000  1.0
  O  O17  1  0.59262900  0.24240000  0.44676700  1.0
  O  O18  1  0.05714100  0.25969700  0.90915500  1.0
  O  O19  1  0.24240000  0.44676700  0.59262900  1.0
  O  O20  1  0.39007600  0.17774900  0.99354300  1.0
  O  O21  1  0.44676700  0.59262900  0.24240000  1.0
  O  O22  1  0.74776700  0.08191000  0.93898000  1.0
  O  O23  1  0.99354300  0.39007600  0.17774900  1.0
  O  O24  1  0.00469800  0.61900000  0.81987800  1.0
  O  O25  1  0.25969700  0.90915500  0.05714100  1.0
  O  O26  1  0.56361200  0.40508800  0.75250600  1.0
  O  O27  1  0.61900000  0.81987800  0.00469800  1.0
  O  O28  1  0.75250600  0.56361200  0.40508800  1.0
  O  O29  1  0.93898000  0.74776700  0.08191000  1.0
  O  O30  1  0.40508800  0.75250600  0.56361200  1.0
  O  O31  1  0.17774900  0.99354300  0.39007600  1.0
  O  O32  1  0.88820000  0.50015400  0.67973400  1.0
  O  O33  1  0.08191000  0.93898000  0.74776700  1.0
  O  O34  1  0.50015400  0.67973400  0.88820000  1.0
  O  O35  1  0.67973400  0.88820000  0.50015400  1.0

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