SrAc(Si2Ir3)2

High-Entropy Materials HEA

MP-ID: mp-3248352 · Space group: Imm2 (#44)

Materials Project API

Basic Information

Formula

SrAc(Si2Ir3)2

MP-ID

mp-3248352

Elements

Sites

Density

12.9066

g/cm³

Volume

203.31

Å³

Cell a

6.7572

Cell b

6.7572

Cell c

6.7572

α Angle

130.01

β Angle

115.90

γ Angle

85.42

Space Group

Imm2

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
15.24	5.8139	18.4	(0,1,-1)
17.86	4.9651	5.5	(1,1,-1)
17.92	4.9500	5.0	(1,0,-1)
17.92	4.9500	5.0	(0,1,0)
19.88	4.4670	14.0	(0,0,1)
24.83	3.5858	57.4	(1,-1,1)
26.85	3.3208	8.2	(1,1,-2)
29.73	3.0054	2.1	(1,2,-2)
29.73	3.0054	2.1	(2,1,-1)
30.76	2.9069	26.5	(0,2,-2)
30.76	2.9069	26.5	(2,0,0)
30.79	2.9039	30.8	(0,1,-2)
30.79	2.9039	92.5	(1,0,1)
35.01	2.5627	1.9	(1,0,-2)
35.01	2.5627	5.6	(2,-1,-1)
36.18	2.4825	100.0	(2,2,-2)
36.30	2.4750	96.8	(2,0,-2)
36.30	2.4750	96.8	(0,2,0)
40.31	2.2377	23.7	(1,2,-3)
40.31	2.2377	71.2	(3,0,-1)
40.38	2.2335	20.3	(0,0,2)
40.38	2.2335	20.3	(2,-2,0)
40.93	2.2051	13.5	(1,-1,2)
41.62	2.1699	1.5	(2,2,-3)

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Energy Properties

Formation Energy/atom

-0.92491

eV/atom

Energy/atom

-37.01110

eV/atom

Energy above Hull

0.0000

eV/atom

Uncorrected Energy

-37.0111

eV/atom

Volume/atom

16.94

Å³

c/a Ratio

1.0000

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 · 0.500

Element Family

5d-TM

Solute Fraction

0.500

Interstitial Fraction

0.333

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.1269

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

9.3693

J/mol·K

Ω Parameter

3.3083

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

19.395%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.4166

smaller = more stable mixing

VEC

6.167

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-6.031

kJ/mol; negative = exothermic mixing

Entropy Norm

0.8129

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (1)

aaahcvgq

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-3248352

Reference Citation

The crystal structure and related material properties of SrAc(Si2Ir3)2 were obtained from the Materials Project database (MP-ID: mp-3248352, 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_SrAc(Si2Ir3)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.75724191
_cell_length_b   6.75724122
_cell_length_c   6.75724300
_cell_angle_alpha   130.01405811
_cell_angle_beta   115.90058188
_cell_angle_gamma   85.42371304
_symmetry_Int_Tables_number   1
_chemical_formula_structural   SrAc(Si2Ir3)2
_chemical_formula_sum   'Sr1 Ac1 Si4 Ir6'
_cell_volume   203.31454049
_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  0.25000000  0.97771533  0.72771533  1.0
  Ac  Ac1  1  0.75000000  0.01991464  0.26991464  1.0
  Si  Si2  1  0.08798264  0.29793807  0.20995543  1.0
  Si  Si3  1  0.92882770  0.72472713  0.79590043  1.0
  Si  Si4  1  0.41201736  0.62197280  0.20995543  1.0
  Si  Si5  1  0.57117230  0.36707273  0.79590043  1.0
  Ir  Ir6  1  0.51087552  0.49702087  0.50789538  1.0
  Ir  Ir7  1  0.98912448  0.49702087  0.98614435  1.0
  Ir  Ir8  1  0.27824931  0.99917035  0.27738574  1.0
  Ir  Ir9  1  0.72178462  0.99917035  0.72092104  1.0
  Ir  Ir10  1  0.22175069  0.49913743  0.72092104  1.0
  Ir  Ir11  1  0.77821538  0.49913743  0.27738574  1.0

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