AcY(Si2Ir3)2

High-Entropy Materials HEA

MP-ID: mp-3252857 · Space group: Imm2 (#44)

Materials Project API

Basic Information

Formula

AcY(Si2Ir3)2

MP-ID

mp-3252857

Elements

Sites

Density

13.1565

g/cm³

Volume

199.61

Å³

Cell a

6.7142

Cell b

6.7142

Cell c

6.7142

α Angle

130.33

β Angle

115.17

γ Angle

85.84

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
15.25	5.8085	7.1	(1,0,0)
18.04	4.9167	4.1	(1,1,-1)
18.13	4.8923	7.5	(1,0,-1)
20.00	4.4396	17.3	(1,-1,0)
24.74	3.5993	45.4	(1,-1,1)
27.06	3.2951	4.8	(2,0,-1)
27.06	3.2951	4.8	(1,1,0)
29.95	2.9831	1.1	(2,1,-1)
29.95	2.9831	1.1	(1,2,-2)
30.79	2.9043	20.5	(2,0,0)
30.79	2.9043	20.5	(0,2,-2)
30.84	2.8992	100.0	(2,-1,0)
35.38	2.5368	3.3	(2,-1,-1)
35.38	2.5368	3.3	(0,1,1)
36.55	2.4583	78.4	(2,2,-2)
36.74	2.4462	74.4	(2,0,-2)
36.74	2.4462	74.4	(0,2,0)
38.62	2.3311	2.6	(2,-1,1)
40.51	2.2266	19.2	(3,0,-1)
40.51	2.2266	38.4	(1,2,-3)
40.51	2.2266	19.2	(0,3,-2)
40.64	2.2198	29.8	(2,-2,0)
40.87	2.2080	9.6	(2,-2,1)
42.01	2.1506	1.9	(3,1,-2)

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Energy Properties

Formation Energy/atom

-1.01371

eV/atom

Energy/atom

-37.53057

eV/atom

Energy above Hull

0.0000

eV/atom

Uncorrected Energy

-37.5306

eV/atom

Volume/atom

16.63

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

1.0198

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

17.219%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.3690

smaller = more stable mixing

VEC

6.250

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-20.140

kJ/mol; negative = exothermic mixing

Entropy Norm

0.8129

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (1)

aaahdbxx

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-3252857

Reference Citation

The crystal structure and related material properties of AcY(Si2Ir3)2 were obtained from the Materials Project database (MP-ID: mp-3252857, 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_AcY(Si2Ir3)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.71421891
_cell_length_b   6.71421692
_cell_length_c   6.71421824
_cell_angle_alpha   130.33109658
_cell_angle_beta   115.16684071
_cell_angle_gamma   85.84475825
_symmetry_Int_Tables_number   1
_chemical_formula_structural   AcY(Si2Ir3)2
_chemical_formula_sum   'Ac1 Y1 Si4 Ir6'
_cell_volume   199.61406429
_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
  Ac  Ac0  1  0.75000000  0.02717988  0.27717988  1.0
  Y  Y1  1  0.25000000  0.95697747  0.70697747  1.0
  Si  Si2  1  0.07966026  0.27772634  0.19806608  1.0
  Si  Si3  1  0.92251320  0.72016207  0.79764787  1.0
  Si  Si4  1  0.42033974  0.61840482  0.19806608  1.0
  Si  Si5  1  0.57748680  0.37513468  0.79764787  1.0
  Ir  Ir6  1  0.49309740  0.49883746  0.49193586  1.0
  Ir  Ir7  1  0.00690260  0.49883746  0.00574005  1.0
  Ir  Ir8  1  0.27547215  0.00117449  0.28766707  1.0
  Ir  Ir9  1  0.71350742  0.00117449  0.72570235  1.0
  Ir  Ir10  1  0.22452785  0.51219592  0.72570235  1.0
  Ir  Ir11  1  0.78649258  0.51219592  0.28766707  1.0

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