SrAcB4Ir5

High-Entropy Materials HEA

MP-ID: mp-3249702 · Space group: Fmm2 (#42)

Materials Project API

Basic Information

Formula

SrAcB4Ir5

MP-ID

mp-3249702

Elements

Sites

Density

13.4502

g/cm³

Volume

162.84

Å³

Cell a

7.6479

Cell b

6.3567

Cell c

5.8125

α Angle

77.73

β Angle

54.31

γ Angle

47.96

Space Group

Fmm2

Point Group

mm2

Crystal System

Orthorhombic

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
15.53	5.7058	13.9	(1,1,0)
17.41	5.0925	28.4	(1,0,1)
19.68	4.5101	5.3	(1,0,0)
19.68	4.5101	5.3	(1,1,1)
23.41	3.7994	13.1	(0,1,-1)
29.71	3.0070	21.3	(1,2,0)
29.71	3.0070	63.9	(2,1,0)
31.36	2.8529	35.2	(2,2,0)
31.80	2.8141	1.8	(1,-1,1)
31.80	2.8141	1.8	(1,0,2)
31.94	2.8020	4.3	(0,1,1)
35.25	2.5463	100.0	(2,0,2)
35.70	2.5151	2.3	(1,2,1)
35.70	2.5151	2.3	(1,0,-1)
36.09	2.4890	85.7	(1,2,-1)
36.60	2.4549	90.9	(1,-1,0)
36.60	2.4549	90.9	(1,1,2)
38.73	2.3252	3.1	(1,-1,2)
39.02	2.3081	12.0	(0,2,-1)
39.02	2.3081	12.0	(3,1,1)
39.02	2.3081	24.1	(0,1,-2)
39.98	2.2551	1.4	(0,2,0)
39.98	2.2551	1.4	(2,0,0)
39.98	2.2551	2.9	(2,2,2)

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Energy Properties

Formation Energy/atom

-0.71433

eV/atom

Energy/atom

-34.80208

eV/atom

Energy above Hull

0.0000

eV/atom

Uncorrected Energy

-34.8021

eV/atom

Volume/atom

14.80

Å³

c/a Ratio

0.7600

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Total Mag. Moment

0.0000

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.000000

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

Ir · 0.455

Element Family

5d-TM

Solute Fraction

0.545

Interstitial Fraction

0.364

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.1622

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

9.6627

J/mol·K

Ω Parameter

2.1320

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

28.962%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.4330

smaller = more stable mixing

VEC

5.545

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-10.492

kJ/mol; negative = exothermic mixing

Entropy Norm

0.8384

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (1)

aaahcxgo

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-3249702

Reference Citation

The crystal structure and related material properties of SrAcB4Ir5 were obtained from the Materials Project database (MP-ID: mp-3249702, 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_SrAcB4Ir5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.64789301
_cell_length_b   6.35669014
_cell_length_c   5.81249978
_cell_angle_alpha   77.73159951
_cell_angle_beta   54.31018354
_cell_angle_gamma   47.95824081
_symmetry_Int_Tables_number   1
_chemical_formula_structural   SrAcB4Ir5
_chemical_formula_sum   'Sr1 Ac1 B4 Ir5'
_cell_volume   162.83585025
_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
  Sr  Sr0  1  0.14639454  0.14639454  0.85360546  1.0
  Ac  Ac1  1  0.86049906  0.86049906  0.13950094  1.0
  B  B2  1  0.78975917  0.46421238  0.53578762  1.0
  B  B3  1  0.20641289  0.53504379  0.46495621  1.0
  B  B4  1  0.53504379  0.20641289  0.79358711  1.0
  B  B5  1  0.46421238  0.78975917  0.21024083  1.0
  Ir  Ir6  1  0.49989423  0.49989423  0.50010577  1.0
  Ir  Ir7  1  0.50053906  0.50053906  0.99946094  1.0
  Ir  Ir8  1  0.00053906  0.00053906  0.49946094  1.0
  Ir  Ir9  1  0.74835241  0.74835241  0.75164759  1.0
  Ir  Ir10  1  0.24835241  0.24835241  0.25164759  1.0

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