Ca(NiO2)2

高熵材料 HEA 传统材料 TRA

MP-ID: mp-1042551 · Space group: C2/m (#12)

Materials Project API

Basic Information

Formula

Ca(NiO2)2

MP-ID

mp-1042551

Elements

Sites

Density

4.7377

g/cm³

Volume

155.24

Å³

Cell a

3.0740

Cell b

7.8994

Cell c

6.7701

α Angle

79.16

β Angle

76.86

γ Angle

78.78

Space Group

C2/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
11.55	7.6602	17.3	(0,1,0)
13.59	6.5177	11.6	(0,0,1)
16.48	5.3796	54.1	(0,1,1)
19.16	4.6319	54.6	(0,1,-1)
25.13	3.5433	1.6	(0,2,1)
27.37	3.2589	2.3	(0,0,2)
28.76	3.1044	25.2	(0,2,-1)
30.24	2.9559	1.9	(1,1,1)
30.24	2.9555	1.9	(1,0,0)
30.64	2.9178	10.9	(1,0,1)
30.65	2.9173	10.9	(1,1,0)
31.41	2.8483	69.6	(0,1,-2)
33.31	2.6898	100.0	(0,2,2)
34.21	2.6214	24.6	(1,2,1)
34.21	2.6212	24.7	(1,-1,0)
35.15	2.5534	39.9	(0,3,0)
35.29	2.5437	19.6	(1,-1,1)
35.29	2.5433	19.8	(1,2,0)
35.75	2.5119	26.7	(1,1,2)
35.76	2.5112	26.5	(1,0,-1)
35.79	2.5092	3.2	(0,3,1)
36.79	2.4432	12.4	(1,0,2)
36.80	2.4425	12.4	(1,1,-1)
39.81	2.2645	1.1	(0,3,-1)

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Energy Properties

Formation Energy/atom

-1.47607

eV/atom

Energy/atom

-6.24146

eV/atom

Energy above Hull

0.1860

eV/atom

Uncorrected Energy

-5.1229

eV/atom

Volume/atom

11.09

Å³

c/a Ratio

2.2024

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

4.0006

μB

Mag. Ordering

FiM

Mag. Sites

Magnetization/Volume

0.025770

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

O · 0.571

Element Family

Metalloid-Nonmetal

Solute Fraction

0.429

Interstitial Fraction

0.000

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

1.6573

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

50.254%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.9497

smaller = more stable mixing

VEC

5.429

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-3.281

kJ/mol; negative = exothermic mixing

Entropy Norm

0.8699

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (3)

aaachigp aaaduqbn aaaefprv

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-1042551

Reference Citation

The crystal structure and related material properties of Ca(NiO2)2 were obtained from the Materials Project database (MP-ID: mp-1042551, 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_Ca(NiO2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.07397165
_cell_length_b   7.89939956
_cell_length_c   6.77008610
_cell_angle_alpha   79.16450951
_cell_angle_beta   76.85893440
_cell_angle_gamma   78.78032370
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ca(NiO2)2
_chemical_formula_sum   'Ca2 Ni4 O8'
_cell_volume   155.24180582
_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
  Ca  Ca0  1  0.34788600  0.16195000  0.15089600  1.0
  Ca  Ca1  1  0.65452900  0.81609400  0.88215000  1.0
  Ni  Ni2  1  0.64018100  0.15620900  0.57156000  1.0
  Ni  Ni3  1  0.13704200  0.52095400  0.21241500  1.0
  Ni  Ni4  1  0.86530400  0.45727400  0.82047400  1.0
  Ni  Ni5  1  0.36206700  0.82196600  0.46155800  1.0
  O  O6  1  0.86642900  0.68575500  0.58846200  1.0
  O  O7  1  0.46198400  0.29346100  0.79074000  1.0
  O  O8  1  0.54037500  0.68454000  0.24241900  1.0
  O  O9  1  0.13577700  0.29236700  0.44469000  1.0
  O  O10  1  0.16076100  0.99369800  0.69248400  1.0
  O  O11  1  0.75358200  0.37475700  0.12587000  1.0
  O  O12  1  0.84173200  0.98428400  0.34045800  1.0
  O  O13  1  0.24866100  0.60349200  0.90726700  1.0

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