Ca9HoIr4

High-Entropy Materials HEA Traditional Materials TRA

MP-ID: mp-3294476 · Space group: C2 (#5)

Materials Project API

Basic Information

Formula

Ca9HoIr4

MP-ID

mp-3294476

Elements

Sites

Density

5.5976

g/cm³

Volume

384.01

Å³

Cell a

6.5078

Cell b

7.5206

Cell c

8.5635

α Angle

97.29

β Angle

112.33

γ Angle

90.00

Space Group

Point Group

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
11.28	7.8463	39.4	(0,0,1)
11.88	7.4495	9.1	(0,1,0)
14.74	6.0113	36.8	(1,0,0)
15.24	5.8155	4.4	(0,1,-1)
17.50	5.0665	1.9	(0,1,1)
18.47	4.8032	11.4	(1,-1,0)
19.46	4.5625	100.0	(1,-1,-1)
22.67	3.9232	18.4	(0,0,2)
23.73	3.7493	67.9	(1,-1,1)
23.89	3.7247	2.9	(0,2,0)
25.02	3.5593	14.9	(0,2,-1)
26.01	3.4255	10.6	(1,1,1)
27.41	3.2539	8.6	(2,0,-1)
27.50	3.2434	2.0	(1,-2,0)
27.89	3.1991	8.8	(0,2,1)
28.85	3.0942	5.4	(1,-2,-1)
29.97	2.9818	3.2	(2,1,-1)
30.73	2.9092	3.8	(1,-2,1)
30.75	2.9077	8.2	(0,2,-2)
31.51	2.8396	22.3	(2,-1,0)
31.65	2.8269	4.4	(1,0,2)
32.46	2.7585	5.8	(1,-1,2)
32.46	2.7585	5.8	(1,1,-3)
32.71	2.7379	17.3	(2,1,0)

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Energy Properties

Formation Energy/atom

-0.42758

eV/atom

Energy/atom

-22.26068

eV/atom

Energy above Hull

0.0000

eV/atom

Uncorrected Energy

-22.2607

eV/atom

Volume/atom

27.43

Å³

c/a Ratio

1.3159

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Total Mag. Moment

0.0002

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

Ca · 0.643

Element Family

Alkali-AlkEarth

Solute Fraction

0.357

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

0.8305

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

6.9045

J/mol·K

Ω Parameter

0.4672

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

15.249%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.5349

smaller = more stable mixing

VEC

4.643

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-23.990

kJ/mol; negative = exothermic mixing

Entropy Norm

0.7559

SS Former

Phase Tendency

Traditional Material Features

ROM Blended-Feature Radar

Rating & Classification

Tier

Score

0.613

Family

Ca-rich Multi-Component

Matrix Element

Ca · 0.643

Related Tasks

Related computation task IDs (1)

aaahflmq

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-3294476

Reference Citation

The crystal structure and related material properties of Ca9HoIr4 were obtained from the Materials Project database (MP-ID: mp-3294476, 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_Ca9HoIr4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.50774873
_cell_length_b   7.52055913
_cell_length_c   8.56347508
_cell_angle_alpha   97.29058316
_cell_angle_beta   112.33189619
_cell_angle_gamma   90.00000375
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ca9HoIr4
_chemical_formula_sum   'Ca9 Ho1 Ir4'
_cell_volume   384.01299791
_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
  Ca  Ca0  1  0.96968128  0.91950519  0.17165683  1.0
  Ca  Ca1  1  0.79802344  0.58049481  0.82834317  1.0
  Ca  Ca2  1  0.02306430  0.08166921  0.82567748  1.0
  Ca  Ca3  1  0.19738682  0.41833079  0.17432252  1.0
  Ca  Ca4  1  0.63761890  0.82297755  0.43335219  1.0
  Ca  Ca5  1  0.20426571  0.67702245  0.56664781  1.0
  Ca  Ca6  1  0.36388785  0.17739745  0.56354071  1.0
  Ca  Ca7  1  0.80034815  0.32260255  0.43645929  1.0
  Ca  Ca8  1  0.42621817  0.75000000  1.00000000  1.0
  Ho  Ho9  1  0.56277318  0.25000000  0.00000000  1.0
  Ir  Ir10  1  0.81596810  0.57087614  0.21204074  1.0
  Ir  Ir11  1  0.60392736  0.92912386  0.78795926  1.0
  Ir  Ir12  1  0.19125274  0.41279497  0.78566874  1.0
  Ir  Ir13  1  0.40558300  0.08720503  0.21433126  1.0

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