CaCu2(NiO4)2

High-Entropy Materials HEA

MP-ID: mp-1047810 · Space group: P2_1/c (#14)

Materials Project API

Basic Information

Formula

CaCu2(NiO4)2

MP-ID

mp-1047810

Elements

Sites

Density

4.1673

g/cm³

Volume

657.56

Å³

Cell a

8.5036

Cell b

6.3958

Cell c

12.1205

α Angle

85.96

β Angle

90.00

γ Angle

90.00

Space Group

P2_1/c

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
13.88	6.3800	17.2	(0,1,0)
17.38	5.1033	23.0	(1,1,0)
18.00	4.9270	2.8	(1,0,2)
19.26	4.6095	1.5	(1,1,-1)
19.50	4.5511	10.5	(0,1,2)
20.89	4.2518	18.7	(2,0,0)
20.94	4.2416	9.1	(0,1,-2)
22.15	4.0126	2.7	(1,1,2)
22.16	4.0110	1.3	(2,0,1)
23.44	3.7956	28.5	(1,1,-2)
24.44	3.6418	45.8	(1,0,3)
25.61	3.4777	33.4	(2,0,2)
25.96	3.4320	13.9	(2,1,1)
26.52	3.3605	20.6	(2,1,-1)
27.42	3.2532	15.5	(1,1,3)
28.73	3.1069	4.5	(2,1,2)
28.99	3.0796	6.7	(1,1,-3)
29.55	3.0226	69.6	(0,0,4)
29.75	3.0028	31.0	(2,1,-2)
29.92	2.9867	19.5	(1,2,0)
30.35	2.9451	100.0	(1,2,1)
30.56	2.9250	2.1	(2,0,3)
30.76	2.9070	1.6	(0,2,2)
31.32	2.8561	17.8	(1,2,-1)

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Energy Properties

Formation Energy/atom

-0.98324

eV/atom

Energy/atom

-5.70232

eV/atom

Energy above Hull

0.3134

eV/atom

Uncorrected Energy

-4.8886

eV/atom

Volume/atom

12.65

Å³

c/a Ratio

1.4253

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

23.9026

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.036350

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

O · 0.615

Element Family

Metalloid-Nonmetal

Solute Fraction

0.385

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.0720

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

8.9127

J/mol·K

Ω Parameter

4.2876

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

47.138%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.8645

smaller = more stable mixing

VEC

5.846

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-1.235

kJ/mol; negative = exothermic mixing

Entropy Norm

0.7733

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (1)

aaaeebcu

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-1047810

Reference Citation

The crystal structure and related material properties of CaCu2(NiO4)2 were obtained from the Materials Project database (MP-ID: mp-1047810, 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_CaCu2(NiO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.50354700
_cell_length_b   6.39584000
_cell_length_c   12.12046004
_cell_angle_alpha   85.96147577
_cell_angle_beta   90.00000000
_cell_angle_gamma   90.00000000
_symmetry_Int_Tables_number   1
_chemical_formula_structural   CaCu2(NiO4)2
_chemical_formula_sum   'Ca4 Cu8 Ni8 O32'
_cell_volume   657.56256886
_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
  Ca  Ca0  1  0.17875100  0.16982600  0.01591100  1.0
  Ca  Ca1  1  0.82124900  0.83017400  0.98408900  1.0
  Ca  Ca2  1  0.67875100  0.83017400  0.48408900  1.0
  Ca  Ca3  1  0.32124900  0.16982600  0.51591100  1.0
  Cu  Cu4  1  0.19396900  0.73123800  0.88217200  1.0
  Cu  Cu5  1  0.03922900  0.41490400  0.64149100  1.0
  Cu  Cu6  1  0.96077100  0.58509600  0.35850900  1.0
  Cu  Cu7  1  0.80603100  0.26876200  0.11782800  1.0
  Cu  Cu8  1  0.30603100  0.73123800  0.38217200  1.0
  Cu  Cu9  1  0.46077100  0.41490400  0.14149100  1.0
  Cu  Cu10  1  0.69396900  0.26876200  0.61782800  1.0
  Cu  Cu11  1  0.53922900  0.58509600  0.85850900  1.0
  Ni  Ni12  1  0.47560800  0.08068000  0.82605600  1.0
  Ni  Ni13  1  0.02439200  0.08068000  0.32605600  1.0
  Ni  Ni14  1  0.10205100  0.61488500  0.13579300  1.0
  Ni  Ni15  1  0.97560800  0.91932000  0.67394400  1.0
  Ni  Ni16  1  0.89794900  0.38511500  0.86420700  1.0
  Ni  Ni17  1  0.60205100  0.38511500  0.36420700  1.0
  Ni  Ni18  1  0.39794900  0.61488500  0.63579300  1.0
  Ni  Ni19  1  0.52439200  0.91932000  0.17394400  1.0
  O  O20  1  0.21268700  0.98925000  0.37965000  1.0
  O  O21  1  0.97691600  0.68603700  0.60133900  1.0
  O  O22  1  0.59870600  0.18517700  0.48015400  1.0
  O  O23  1  0.09870600  0.81482300  0.01984600  1.0
  O  O24  1  0.28731300  0.98925000  0.87965000  1.0
  O  O25  1  0.78731300  0.01075000  0.62035000  1.0
  O  O26  1  0.10494200  0.13976000  0.65054400  1.0
  O  O27  1  0.89976000  0.53134300  0.11879100  1.0
  O  O28  1  0.60024000  0.53134300  0.61879100  1.0
  O  O29  1  0.85207600  0.35674900  0.71553200  1.0
  O  O30  1  0.35207600  0.64325100  0.78446800  1.0
  O  O31  1  0.10024000  0.46865700  0.88120900  1.0
  O  O32  1  0.89505800  0.86024000  0.34945600  1.0
  O  O33  1  0.51192300  0.84470000  0.31386500  1.0
  O  O34  1  0.23076900  0.47265100  0.58069800  1.0
  O  O35  1  0.26923100  0.47265100  0.08069800  1.0
  O  O36  1  0.01192300  0.15530000  0.18613500  1.0
  O  O37  1  0.39976000  0.46865700  0.38120900  1.0
  O  O38  1  0.48807700  0.15530000  0.68613500  1.0
  O  O39  1  0.40129400  0.81482300  0.51984600  1.0
  O  O40  1  0.52308400  0.68603700  0.10133900  1.0
  O  O41  1  0.14792400  0.64325100  0.28446800  1.0
  O  O42  1  0.71268700  0.01075000  0.12035000  1.0
  O  O43  1  0.39505800  0.13976000  0.15054400  1.0
  O  O44  1  0.90129400  0.18517700  0.98015400  1.0
  O  O45  1  0.73076900  0.52734900  0.91930200  1.0
  O  O46  1  0.02308400  0.31396300  0.39866100  1.0
  O  O47  1  0.47691600  0.31396300  0.89866100  1.0
  O  O48  1  0.60494200  0.86024000  0.84945600  1.0
  O  O49  1  0.76923100  0.52734900  0.41930200  1.0
  O  O50  1  0.64792400  0.35674900  0.21553200  1.0
  O  O51  1  0.98807700  0.84470000  0.81386500  1.0

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