CoNi(PO4)2

High-Entropy Materials HEA

MP-ID: mp-765340 · Space group: P2_1/m (#11)

Materials Project API

Basic Information

Formula

CoNi(PO4)2

MP-ID

mp-765340

Elements

Sites

Density

3.7206

g/cm³

Volume

274.55

Å³

Cell a

5.8025

Cell b

4.7874

Cell c

9.8834

α Angle

89.70

β Angle

90.00

γ Angle

90.00

Space Group

P2_1/m

Point Group

2/m

Crystal System

Monoclinic

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
17.95	4.9417	99.3	(0,0,2)
20.57	4.3172	54.6	(0,1,1)
20.66	4.2998	55.6	(0,1,-1)
23.65	3.7622	22.8	(1,0,2)
25.72	3.4637	60.2	(1,1,1)
25.79	3.4546	73.4	(1,1,-1)
25.84	3.4473	11.7	(0,1,2)
25.98	3.4296	8.2	(0,1,-2)
30.15	2.9637	18.5	(1,1,2)
30.27	2.9524	15.2	(1,1,-2)
30.82	2.9013	100.0	(2,0,0)
32.92	2.7205	10.7	(0,1,3)
33.09	2.7074	7.8	(0,1,-3)
35.89	2.5019	4.5	(2,0,2)
36.48	2.4632	65.0	(1,1,3)
36.63	2.4535	68.5	(1,1,-3)
37.34	2.4080	18.3	(2,1,1)
37.39	2.4050	18.3	(2,1,-1)
38.66	2.3292	14.0	(0,2,1)
38.75	2.3236	11.7	(0,2,-1)
39.65	2.2733	16.2	(1,0,4)
40.64	2.2198	4.2	(2,1,2)
40.74	2.2150	8.4	(2,1,-2)
41.02	2.2003	12.9	(0,1,4)

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Energy Properties

Formation Energy/atom

-1.90812

eV/atom

Energy/atom

-7.18547

eV/atom

Energy above Hull

0.1736

eV/atom

Uncorrected Energy

-6.3792

eV/atom

Volume/atom

11.44

Å³

c/a Ratio

1.7033

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

2.1343

μB

Mag. Ordering

FiM

Mag. Sites

Magnetization/Volume

0.007770

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

0.9831

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

8.1734

J/mol·K

Ω Parameter

2.9207

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

34.535%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.6643

smaller = more stable mixing

VEC

5.083

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-1.066

kJ/mol; negative = exothermic mixing

Entropy Norm

0.7091

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (2)

aaabzdly aaacyhea

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-765340

Reference Citation

The crystal structure and related material properties of CoNi(PO4)2 were obtained from the Materials Project database (MP-ID: mp-765340, 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_CoNi(PO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.80250700
_cell_length_b   4.78736300
_cell_length_c   9.88343329
_cell_angle_alpha   89.70354964
_cell_angle_beta   90.00000000
_cell_angle_gamma   90.00000000
_symmetry_Int_Tables_number   1
_chemical_formula_structural   CoNi(PO4)2
_chemical_formula_sum   'Co2 Ni2 P4 O16'
_cell_volume   274.54532582
_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
  Co  Co0  1  0.25000000  0.94541900  0.72081900  1.0
  Co  Co1  1  0.75000000  0.05458100  0.27918100  1.0
  Ni  Ni2  1  0.75000000  0.45336700  0.77226900  1.0
  Ni  Ni3  1  0.25000000  0.54663300  0.22773100  1.0
  P  P4  1  0.25000000  0.39964900  0.90210100  1.0
  P  P5  1  0.75000000  0.92052200  0.59255700  1.0
  P  P6  1  0.25000000  0.07947800  0.40744300  1.0
  P  P7  1  0.75000000  0.60035100  0.09789900  1.0
  O  O8  1  0.75000000  0.65831400  0.94599700  1.0
  O  O9  1  0.25000000  0.72015900  0.88236300  1.0
  O  O10  1  0.04516600  0.25113500  0.82871800  1.0
  O  O11  1  0.45483400  0.25113500  0.82871800  1.0
  O  O12  1  0.54215200  0.77346100  0.66864300  1.0
  O  O13  1  0.95784800  0.77346100  0.66864300  1.0
  O  O14  1  0.75000000  0.23568600  0.60396400  1.0
  O  O15  1  0.25000000  0.16928400  0.55688000  1.0
  O  O16  1  0.75000000  0.83071600  0.44312000  1.0
  O  O17  1  0.25000000  0.76431400  0.39603600  1.0
  O  O18  1  0.04215200  0.22653900  0.33135700  1.0
  O  O19  1  0.45784800  0.22653900  0.33135700  1.0
  O  O20  1  0.54516600  0.74886500  0.17128200  1.0
  O  O21  1  0.95483400  0.74886500  0.17128200  1.0
  O  O22  1  0.75000000  0.27984100  0.11763700  1.0
  O  O23  1  0.25000000  0.34168600  0.05400300  1.0

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