Ca(FeAs)2

High-Entropy Materials HEA Traditional Materials TRA Elasticity Data ELA

MP-ID: mp-1068300 · Space group: I4/mmm (#139)

Materials Project API

Basic Information

Formula

Ca(FeAs)2

MP-ID

mp-1068300

Elements

Sites

Density

5.6284

g/cm³

Volume

177.97

Å³

Cell a

5.4880

Cell b

6.5105

Cell c

5.4952

α Angle

65.01

β Angle

90.00

γ Angle

90.00

Space Group

I4/mmm

Point Group

4/mmm

Crystal System

Tetragonal

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
15.01	5.9012	100.0	(0,1,0)
24.13	3.6889	26.9	(1,1,1)
24.13	3.6889	26.9	(1,-1,-1)
24.13	3.6884	27.0	(1,0,-1)
24.13	3.6883	27.0	(1,0,1)
32.39	2.7641	62.3	(1,2,1)
32.39	2.7640	62.3	(1,-2,-1)
32.40	2.7633	62.2	(1,1,-1)
32.40	2.7632	62.2	(1,-1,1)
32.59	2.7476	16.9	(0,1,2)
32.63	2.7440	16.9	(2,0,0)
36.05	2.4912	55.1	(0,2,2)
36.06	2.4905	55.2	(0,0,2)
36.10	2.4882	55.0	(2,1,0)
36.10	2.4881	55.0	(2,-1,0)
44.93	2.0173	26.6	(1,3,1)
44.94	2.0173	26.6	(1,-3,-1)
44.95	2.0168	26.6	(1,2,-1)
44.95	2.0168	26.5	(1,-2,1)
45.08	2.0112	58.2	(0,3,2)
45.10	2.0104	58.2	(0,1,-2)
45.12	2.0094	58.1	(2,2,0)
45.12	2.0093	58.1	(2,-2,0)
46.15	1.9671	7.0	(0,3,0)

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Energy Properties

Formation Energy/atom

-0.53034

eV/atom

Energy/atom

-6.18752

eV/atom

Energy above Hull

0.0000

eV/atom

Uncorrected Energy

-13.5813

eV/atom

Volume/atom

17.80

Å³

c/a Ratio

1.0013

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

11.3368

μB

Mag. Ordering

Unknown

Mag. Sites

Magnetization/Volume

0.063700

μB/Å³

Elastic Properties

K_VRH

56.912

GPa

G_VRH

25.387

GPa

Young's Modulus E

66.302

GPa

Poisson Ratio ν

0.306

Pugh Ratio K/G

2.242

Vickers Hardness Est.

2.159

GPa

Ductility

Brittle

Anisotropy

-0.568

Lame λ

39.987

GPa

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

Fe · 0.400

Element Family

3d-TM

Solute Fraction

0.600

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.0549

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

8.7706

J/mol·K

Ω Parameter

1.8958

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

22.822%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.4314

smaller = more stable mixing

VEC

4.800

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

6.400

kJ/mol; negative = exothermic mixing

Entropy Norm

0.9602

SS Former

Phase Tendency

Traditional Material Features

ROM Blended-Feature Radar

Rating & Classification

Tier

Score

0.580

Family

Fe-rich Multi-Component

Matrix Element

Fe · 0.400

Elasticity Features

Elastic Modulus Comparison (GPa)

Elastic Features

Elastic Anisotropy A^U

-0.5680

Homogeneous Poisson ν

0.3060

Debye Temperature

340.3

Sound Velocity

2,374.0

m/s

Homogeneity

0.3060

Related Tasks

Related computation task IDs (5)

aaacivgd aaadrcdc aaaektok aaaeusht aaafxhpi

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-1068300

Reference Citation

The crystal structure and related material properties of Ca(FeAs)2 were obtained from the Materials Project database (MP-ID: mp-1068300, 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_Ca(FeAs)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.48800167
_cell_length_b   6.51045827
_cell_length_c   5.49520747
_cell_angle_alpha   65.01488176
_cell_angle_beta   90.00086560
_cell_angle_gamma   89.99818649
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ca(FeAs)2
_chemical_formula_sum   'Ca2 Fe4 As4'
_cell_volume   177.96646804
_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  0.49998660  0.00000577  0.49999681  1.0
  Ca  Ca1  1  0.00000311  0.00000562  -0.00000237  1.0
  Fe  Fe2  1  0.25004727  0.50000810  -0.00000356  1.0
  Fe  Fe3  1  0.74993900  0.50000171  0.00001414  1.0
  Fe  Fe4  1  0.75002043  0.49999034  0.49998570  1.0
  Fe  Fe5  1  0.24996672  0.50001850  0.49998414  1.0
  As  As6  1  0.50006668  0.75249973  0.12368344  1.0
  As  As7  1  -0.00005391  0.75245368  0.62368511  1.0
  As  As8  1  0.00001824  0.24751812  0.37633828  1.0
  As  As9  1  0.50000485  0.24749842  0.87631831  1.0

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