CaFeAsF

High-Entropy Materials HEA

MP-ID: mp-1080591 · Space group: P4/nmm (#129)

Materials Project API

Basic Information

Formula

CaFeAsF

MP-ID

mp-1080591

Elements

Sites

Density

4.3055

g/cm³

Volume

146.44

Å³

Cell a

4.0566

Cell b

4.0566

Cell c

8.8989

α Angle

90.00

β Angle

90.00

γ Angle

90.00

Space Group

P4/nmm

Point Group

4/mmm

Crystal System

Tetragonal

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
9.94	8.8989	63.8	(0,0,1)
19.96	4.4495	3.4	(0,0,2)
24.11	3.6911	20.5	(1,0,1)
29.80	2.9977	100.0	(1,0,2)
31.18	2.8684	6.8	(1,1,0)
32.80	2.7301	7.2	(1,1,1)
37.30	2.4109	95.7	(1,1,2)
37.56	2.3944	5.4	(1,0,3)
43.91	2.0620	19.6	(1,1,3)
44.68	2.0283	58.7	(2,0,0)
45.89	1.9776	6.7	(2,0,1)
46.56	1.9506	24.1	(1,0,4)
51.34	1.7798	5.7	(0,0,5)
51.40	1.7776	5.8	(2,1,1)
52.02	1.7580	32.9	(1,1,4)
54.63	1.6799	33.6	(2,1,2)
59.75	1.5477	2.6	(2,1,3)
62.64	1.4832	8.0	(0,0,6)
65.03	1.4342	17.5	(2,2,0)
65.98	1.4159	2.3	(2,2,1)
66.50	1.4060	16.0	(2,1,4)
70.38	1.3378	8.7	(2,0,5)
70.43	1.3368	1.2	(3,0,1)
73.15	1.2938	6.8	(3,0,2)

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Energy Properties

Formation Energy/atom

-1.60057

eV/atom

Energy/atom

-5.86565

eV/atom

Energy above Hull

0.3142

eV/atom

Uncorrected Energy

-5.1862

eV/atom

Volume/atom

18.30

Å³

c/a Ratio

2.1937

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

7.5970

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.051880

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

Ca · 0.250

Element Family

Alkali-AlkEarth

Solute Fraction

0.750

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.3863

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

11.5257

J/mol·K

Ω Parameter

2.3452

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

42.737%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

1.0882

smaller = more stable mixing

VEC

4.500

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

5.000

kJ/mol; negative = exothermic mixing

Entropy Norm

1.0000

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (5)

aaadmwju aaadrcfj aaadwvps aaaerclx aaafwxol

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-1080591

Reference Citation

The crystal structure and related material properties of CaFeAsF were obtained from the Materials Project database (MP-ID: mp-1080591, 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_CaFeAsF
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.05656000
_cell_length_b   4.05656000
_cell_length_c   8.89893900
_cell_angle_alpha   90.00000000
_cell_angle_beta   90.00000000
_cell_angle_gamma   90.00000000
_symmetry_Int_Tables_number   1
_chemical_formula_structural   CaFeAsF
_chemical_formula_sum   'Ca2 Fe2 As2 F2'
_cell_volume   146.43808392
_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  0.50000000  0.00000000  0.85555300  1.0
  Ca  Ca1  1  0.00000000  0.50000000  0.14444700  1.0
  Fe  Fe2  1  0.00000000  0.00000000  0.50000000  1.0
  Fe  Fe3  1  0.50000000  0.50000000  0.50000000  1.0
  As  As4  1  0.50000000  0.00000000  0.32254100  1.0
  As  As5  1  0.00000000  0.50000000  0.67745900  1.0
  F  F6  1  0.00000000  0.00000000  0.00000000  1.0
  F  F7  1  0.50000000  0.50000000  0.00000000  1.0

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