NaFeAs

High-Entropy Materials HEA Traditional Materials TRA

MP-ID: mp-1077240 · Space group: Cmcm (#63)

Materials Project API

Basic Information

Formula

NaFeAs

MP-ID

mp-1077240

Elements

Sites

Density

4.6078

g/cm³

Volume

110.82

Å³

Cell a

7.5000

Cell b

7.5000

Cell c

3.9729

α Angle

90.00

β Angle

90.00

γ Angle

150.27

Space Group

Cmcm

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
12.21	7.2490	100.0	(1,-1,0)
23.93	3.7192	2.4	(1,0,0)
25.57	3.4840	11.2	(1,-1,1)
29.68	3.0103	20.4	(2,-1,0)
32.99	2.7151	1.9	(1,0,1)
33.47	2.6776	16.5	(2,-2,1)
37.48	2.3993	30.4	(2,-1,1)
38.89	2.3157	4.5	(3,-2,0)
45.33	2.0007	31.1	(3,-2,1)
45.67	1.9865	13.3	(0,0,2)
47.24	1.9240	12.0	(1,1,0)
47.46	1.9158	6.2	(1,-1,2)
48.98	1.8596	5.6	(2,0,0)
50.01	1.8238	3.8	(4,-3,0)
54.48	1.6842	2.8	(2,0,1)
55.42	1.6580	6.8	(2,-1,2)
55.44	1.6575	11.5	(4,-3,1)
55.75	1.6488	5.6	(4,-4,1)
59.13	1.5625	6.1	(3,-1,1)
61.50	1.5077	2.2	(3,-2,2)
62.51	1.4859	2.3	(5,-4,0)
64.25	1.4498	1.8	(5,-5,0)
67.27	1.3918	2.1	(5,-4,1)
67.81	1.3820	7.6	(1,1,2)

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Energy Properties

Formation Energy/atom

-0.21611

eV/atom

Energy/atom

-5.04340

eV/atom

Energy above Hull

0.0525

eV/atom

Uncorrected Energy

-5.0434

eV/atom

Volume/atom

18.47

Å³

c/a Ratio

0.5297

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Total Mag. Moment

0.0006

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.000010

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

Na · 0.333

Element Family

Alkali-AlkEarth

Solute Fraction

0.667

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.0986

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

9.1339

J/mol·K

Ω Parameter

8.0020

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

21.922%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.5265

smaller = more stable mixing

VEC

4.000

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

1.245

kJ/mol; negative = exothermic mixing

Entropy Norm

1.0000

SS Former

Phase Tendency

Traditional Material Features

ROM Blended-Feature Radar

Rating & Classification

Tier

Score

0.315

Family

Na-rich Multi-Component

Matrix Element

Na · 0.333

Related Tasks

Related computation task IDs (5)

aaadoknt aaadtsqy aaadypgg aaaespia aaafbmpu

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-1077240

Reference Citation

The crystal structure and related material properties of NaFeAs were obtained from the Materials Project database (MP-ID: mp-1077240, 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_NaFeAs
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.50001057
_cell_length_b   7.50001057
_cell_length_c   3.97291800
_cell_angle_alpha   90.00000000
_cell_angle_beta   90.00000000
_cell_angle_gamma   150.27181569
_symmetry_Int_Tables_number   1
_chemical_formula_structural   NaFeAs
_chemical_formula_sum   'Na2 Fe2 As2'
_cell_volume   110.81922513
_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
  Na  Na0  1  0.08668800  0.91331200  0.75000000  1.0
  Na  Na1  1  0.91331200  0.08668800  0.25000000  1.0
  Fe  Fe2  1  0.74916200  0.25083800  0.75000000  1.0
  Fe  Fe3  1  0.25083800  0.74916200  0.25000000  1.0
  As  As4  1  0.33826300  0.66173700  0.75000000  1.0
  As  As5  1  0.66173700  0.33826300  0.25000000  1.0

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