Ca4As7Ir8

High-Entropy Materials HEA Traditional Materials TRA

MP-ID: mp-31234 · Space group: P2_1/m (#11)

Materials Project API

Basic Information

Formula

Ca4As7Ir8

MP-ID

mp-31234

Elements

Sites

Density

10.3857

g/cm³

Volume

710.70

Å³

Cell a

4.0864

Cell b

12.9779

Cell c

13.5409

α Angle

81.76

β Angle

90.00

γ Angle

90.00

Space Group

P2_1/m

Point Group

2/m

Crystal System

Monoclinic

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
6.60	13.4011	10.8	(0,0,1)
6.88	12.8440	2.8	(0,1,0)
10.20	8.6727	5.8	(0,1,-1)
13.21	6.7006	33.9	(0,0,2)
13.79	6.4220	40.8	(0,2,0)
14.41	6.1447	9.9	(0,2,1)
15.77	5.6197	5.6	(0,1,-2)
16.14	5.4927	21.7	(0,2,-1)
17.71	5.0088	8.7	(0,2,2)
19.88	4.4670	3.3	(0,0,3)
20.09	4.4203	98.3	(0,1,3)
20.48	4.3363	29.8	(0,2,-2)
20.75	4.2813	48.0	(0,3,0)
20.86	4.2590	28.7	(0,3,1)
21.98	4.0432	4.8	(0,1,-3)
22.56	3.9415	5.8	(0,2,3)
22.75	3.9087	6.4	(1,0,1)
22.84	3.8941	14.9	(1,1,0)
23.51	3.7837	24.0	(1,1,1)
24.07	3.6966	10.1	(1,1,-1)
25.88	3.4431	5.4	(0,2,-3)
26.19	3.4027	3.9	(1,2,1)
26.26	3.3938	9.5	(0,3,-2)
26.61	3.3503	2.0	(0,0,4)

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Energy Properties

Formation Energy/atom

-0.74515

eV/atom

Energy/atom

-29.69150

eV/atom

Energy above Hull

0.0000

eV/atom

Uncorrected Energy

-29.6915

eV/atom

Volume/atom

18.70

Å³

c/a Ratio

3.3137

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 · 0.421

Element Family

5d-TM

Solute Fraction

0.579

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.0601

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

8.8138

J/mol·K

Ω Parameter

1.3623

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

21.493%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.4855

smaller = more stable mixing

VEC

5.316

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-11.578

kJ/mol; negative = exothermic mixing

Entropy Norm

0.9650

SS Former

Phase Tendency

Traditional Material Features

ROM Blended-Feature Radar

Rating & Classification

Tier

Score

0.423

Family

Ir-rich Multi-Component

Matrix Element

Ir · 0.421

Related Tasks

Related computation task IDs (2)

aaadroug aaagagbf

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-31234

Reference Citation

The crystal structure and related material properties of Ca4As7Ir8 were obtained from the Materials Project database (MP-ID: mp-31234, 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_Ca4As7Ir8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.08638844
_cell_length_b   12.97791693
_cell_length_c   13.54085527
_cell_angle_alpha   81.76102474
_cell_angle_beta   90.00000000
_cell_angle_gamma   90.00000000
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ca4As7Ir8
_chemical_formula_sum   'Ca8 As14 Ir16'
_cell_volume   710.69797650
_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  0.25000000  0.10138623  0.79775256  1.0
  Ca  Ca1  1  0.75000000  0.89861377  0.20224744  1.0
  Ca  Ca2  1  0.25000000  0.28857128  0.10535851  1.0
  Ca  Ca3  1  0.75000000  0.71142872  0.89464149  1.0
  Ca  Ca4  1  0.25000000  0.51444217  0.29033457  1.0
  Ca  Ca5  1  0.75000000  0.48555783  0.70966543  1.0
  Ca  Ca6  1  0.25000000  0.21408852  0.43290805  1.0
  Ca  Ca7  1  0.75000000  0.78591148  0.56709195  1.0
  As  As8  1  0.25000000  0.05997378  0.10094802  1.0
  As  As9  1  0.75000000  0.94002622  0.89905198  1.0
  As  As10  1  0.25000000  0.30897444  0.68909163  1.0
  As  As11  1  0.75000000  0.69102556  0.31090837  1.0
  As  As12  1  0.25000000  0.60853623  0.56576833  1.0
  As  As13  1  0.75000000  0.39146377  0.43423167  1.0
  As  As14  1  0.25000000  0.84842958  0.72014307  1.0
  As  As15  1  0.75000000  0.15157042  0.27985693  1.0
  As  As16  1  0.75000000  0.25600912  0.91975581  1.0
  As  As17  1  0.25000000  0.74399088  0.08024419  1.0
  As  As18  1  0.75000000  0.09629114  0.58499235  1.0
  As  As19  1  0.25000000  0.90370886  0.41500765  1.0
  As  As20  1  0.75000000  0.46923807  0.12828682  1.0
  As  As21  1  0.25000000  0.53076193  0.87171318  1.0
  Ir  Ir22  1  0.25000000  0.98587730  0.57266770  1.0
  Ir  Ir23  1  0.75000000  0.01412270  0.42733230  1.0
  Ir  Ir24  1  0.25000000  0.66517137  0.72922048  1.0
  Ir  Ir25  1  0.75000000  0.33482863  0.27077952  1.0
  Ir  Ir26  1  0.25000000  0.55492212  0.04811478  1.0
  Ir  Ir27  1  0.75000000  0.44507788  0.95188522  1.0
  Ir  Ir28  1  0.25000000  0.05382279  0.27990496  1.0
  Ir  Ir29  1  0.75000000  0.94617721  0.72009504  1.0
  Ir  Ir30  1  0.25000000  0.42460672  0.52754528  1.0
  Ir  Ir31  1  0.75000000  0.57539328  0.47245472  1.0
  Ir  Ir32  1  0.25000000  0.92050691  0.99815777  1.0
  Ir  Ir33  1  0.75000000  0.07949309  0.00184223  1.0
  Ir  Ir34  1  0.25000000  0.72126383  0.40050574  1.0
  Ir  Ir35  1  0.75000000  0.27873617  0.59949426  1.0
  Ir  Ir36  1  0.25000000  0.34177505  0.86046102  1.0
  Ir  Ir37  1  0.75000000  0.65822495  0.13953898  1.0

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