Al(NiO2)2

High-Entropy Materials HEA Traditional Materials TRA

MP-ID: mp-1045504 · Space group: Imma (#74)

Materials Project API

Basic Information

Formula

Al(NiO2)2

MP-ID

mp-1045504

Elements

Sites

Density

5.0433

g/cm³

Volume

137.21

Å³

Cell a

5.7862

Cell b

5.7863

Cell c

5.7943

α Angle

120.01

β Angle

120.05

γ Angle

89.87

Space Group

Imma

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
18.77	4.7279	13.0	(1,0,-1)
18.77	4.7279	13.0	(0,1,0)
18.78	4.7263	1.7	(0,1,-1)
18.78	4.7261	1.7	(1,0,0)
21.70	4.0960	36.3	(1,1,-1)
30.86	2.8972	40.3	(1,1,-2)
30.87	2.8970	40.3	(1,1,0)
30.89	2.8947	100.0	(1,-1,-1)
30.91	2.8931	40.0	(0,2,-1)
30.91	2.8931	7.8	(1,-1,1)
30.91	2.8931	40.0	(2,0,-1)
36.36	2.4710	29.0	(1,0,-2)
36.36	2.4710	29.0	(0,1,1)
36.37	2.4703	73.1	(0,1,-2)
36.37	2.4702	73.1	(1,0,1)
36.38	2.4697	70.3	(2,1,-2)
36.38	2.4697	70.3	(1,2,-1)
36.38	2.4695	30.5	(1,2,-2)
36.38	2.4694	30.5	(2,1,-1)
36.43	2.4660	29.3	(1,-2,0)
36.43	2.4660	29.3	(2,-1,-1)
36.45	2.4653	73.5	(1,-2,1)
36.45	2.4653	73.5	(2,-1,0)
38.07	2.3640	5.0	(2,0,-2)

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Energy Properties

Formation Energy/atom

-1.82219

eV/atom

Energy/atom

-6.83615

eV/atom

Energy above Hull

0.1026

eV/atom

Uncorrected Energy

-5.7176

eV/atom

Volume/atom

9.80

Å³

c/a Ratio

1.0014

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

10.0007

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.072890

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

O · 0.571

Element Family

Metalloid-Nonmetal

Solute Fraction

0.429

Interstitial Fraction

0.000

High-Entropy Alloy Features

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

1.4564

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

39.156%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.8119

smaller = more stable mixing

VEC

5.571

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-3.592

kJ/mol; negative = exothermic mixing

Entropy Norm

0.8699

SS Former

Phase Tendency

Traditional Material Features

ROM Blended-Feature Radar

Rating & Classification

Tier

Score

0.494

Family

O-rich Multi-Component

Matrix Element

O · 0.571

Related Tasks

Related computation task IDs (4)

aaachmqo aaadvftu aaadxiuf aaaeplry

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-1045504

Reference Citation

The crystal structure and related material properties of Al(NiO2)2 were obtained from the Materials Project database (MP-ID: mp-1045504, 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

Loading 3D structure…

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Raw CIF Data

# generated using pymatgen
data_Al(NiO2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.78617820
_cell_length_b   5.78626937
_cell_length_c   5.79430356
_cell_angle_alpha   120.00934191
_cell_angle_beta   120.04545189
_cell_angle_gamma   89.87465539
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Al(NiO2)2
_chemical_formula_sum   'Al2 Ni4 O8'
_cell_volume   137.21152663
_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
  Al  Al0  1  0.00001100  0.50000600  0.00000700  1.0
  Al  Al1  1  0.00000400  0.00000400  0.50001100  1.0
  Ni  Ni2  1  0.37116300  0.62118700  0.74999200  1.0
  Ni  Ni3  1  0.62886700  0.37881700  0.25002700  1.0
  Ni  Ni4  1  0.49999500  0.00001000  0.49999700  1.0
  Ni  Ni5  1  0.00000100  0.99998200  0.99997800  1.0
  O  O6  1  0.76711300  0.77396800  0.50843900  1.0
  O  O7  1  0.76553400  0.25866700  0.99154300  1.0
  O  O8  1  0.22319400  0.24816500  0.97364000  1.0
  O  O9  1  0.23286400  0.22603700  0.49155000  1.0
  O  O10  1  0.22543000  0.75045800  0.47360100  1.0
  O  O11  1  0.23445200  0.74132500  0.00843200  1.0
  O  O12  1  0.77455200  0.24953100  0.52640800  1.0
  O  O13  1  0.77681900  0.75184800  0.02637600  1.0

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