Ca8Mn2CoN8

High-Entropy Materials HEA

MP-ID: mp-3296727 · Space group: C2/m (#12)

Materials Project API

Basic Information

Formula

Ca8Mn2CoN8

MP-ID

mp-3296727

Elements

Sites

Density

3.3130

g/cm³

Volume

301.47

Å³

Cell a

9.2017

Cell b

4.9719

Cell c

7.0975

α Angle

90.00

β Angle

75.23

γ Angle

74.33

Space Group

C2/m

Point Group

2/m

Crystal System

Monoclinic

Bravais Lattice

Stability

Yes

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
10.35	8.5433	3.6	(1,0,0)
14.28	6.2027	3.3	(1,0,1)
18.63	4.7616	13.8	(1,0,-1)
20.79	4.2717	3.6	(2,0,0)
21.41	4.1509	3.2	(2,0,1)
21.90	4.0589	35.2	(0,1,-1)
23.76	3.7455	18.5	(2,1,0)
27.38	3.2571	5.3	(2,0,-1)
28.79	3.1013	12.8	(2,0,2)
29.10	3.0684	1.5	(2,1,-1)
29.10	3.0684	1.5	(1,-1,-1)
30.61	2.9210	10.9	(1,0,-2)
30.64	2.9175	10.9	(3,0,1)
31.01	2.8842	15.8	(0,1,-2)
31.01	2.8842	15.8	(1,1,2)
31.41	2.8478	20.2	(3,0,0)
31.61	2.8308	15.7	(3,1,1)
31.61	2.8308	15.7	(2,-1,1)
31.77	2.8162	12.6	(3,1,0)
31.77	2.8162	12.6	(2,-1,0)
32.21	2.7788	10.1	(1,-1,2)
33.32	2.6887	28.6	(1,1,-2)
33.32	2.6887	28.6	(0,1,2)
35.26	2.5453	3.2	(3,0,2)

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Energy Properties

Formation Energy/atom

-1.01276

eV/atom

Energy/atom

-10.06209

eV/atom

Energy above Hull

0.0000

eV/atom

Uncorrected Energy

-10.0621

eV/atom

Volume/atom

15.87

Å³

c/a Ratio

0.7713

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

5.0034

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.016600

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

Ca · 0.421

Element Family

Alkali-AlkEarth

Solute Fraction

0.579

Interstitial Fraction

0.421

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.1204

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

9.3147

J/mol·K

Ω Parameter

0.0725

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

41.710%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.9472

smaller = more stable mixing

VEC

4.158

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-96.180

kJ/mol; negative = exothermic mixing

Entropy Norm

0.8082

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (1)

aaahfovf

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-3296727

Reference Citation

The crystal structure and related material properties of Ca8Mn2CoN8 were obtained from the Materials Project database (MP-ID: mp-3296727, 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_Ca8Mn2CoN8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.20165480
_cell_length_b   4.97188510
_cell_length_c   7.09749062
_cell_angle_alpha   90.00001181
_cell_angle_beta   75.23053599
_cell_angle_gamma   74.32604920
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ca8Mn2CoN8
_chemical_formula_sum   'Ca8 Mn2 Co1 N8'
_cell_volume   301.47489810
_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
  Ca  Ca0  1  0.05318003  0.97341048  0.74510794  1.0
  Ca  Ca1  1  0.94681997  0.02658952  0.25489206  1.0
  Ca  Ca2  1  0.67326721  0.66336589  0.47049259  1.0
  Ca  Ca3  1  0.32673279  0.33663411  0.52950741  1.0
  Ca  Ca4  1  0.81133207  0.59433447  0.96688714  1.0
  Ca  Ca5  1  0.18866793  0.40566553  0.03311286  1.0
  Ca  Ca6  1  0.40061980  0.79969060  0.19110217  1.0
  Ca  Ca7  1  0.59938020  0.20030940  0.80889783  1.0
  Mn  Mn8  1  0.37618507  0.81190697  0.78941881  1.0
  Mn  Mn9  1  0.62381493  0.18809303  0.21058119  1.0
  Co  Co10  1  0.00000000  0.50000000  0.50000000  1.0
  N  N11  1  0.21045417  0.89477192  0.99459859  1.0
  N  N12  1  0.78954583  0.10522808  0.00540141  1.0
  N  N13  1  0.35028748  0.82485626  0.55980689  1.0
  N  N14  1  0.64971252  0.17514374  0.44019311  1.0
  N  N15  1  0.56230284  0.71884808  0.82691926  1.0
  N  N16  1  0.43769716  0.28115192  0.17308074  1.0
  N  N17  1  0.94585709  0.52707045  0.27475827  1.0
  N  N18  1  0.05414291  0.47292955  0.72524173  1.0

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