CaPa3(Al3Rh)6

High-Entropy Materials HEA

MP-ID: mp-3294552 · Space group: Pm (#6)

Materials Project API

Basic Information

Formula

CaPa3(Al3Rh)6

MP-ID

mp-3294552

Elements

Sites

Density

6.5504

g/cm³

Volume

465.50

Å³

Cell a

7.5731

Cell b

7.5797

Cell c

9.3158

α Angle

90.00

β Angle

90.00

γ Angle

119.48

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
9.49	9.3158	32.7	(0,0,0,1)
13.43	6.5925	54.2	(1,0,-1,0)
13.53	6.5441	41.9	(1,-1,0,0)
16.46	5.3845	78.1	(0,1,-1,1)
16.47	5.3814	17.4	(1,0,-1,1)
16.55	5.3549	17.3	(1,-1,0,1)
23.30	3.8179	10.1	(1,1,-2,0)
23.38	3.8042	28.5	(1,0,-1,2)
23.44	3.7948	21.0	(1,-1,0,2)
23.47	3.7897	7.7	(1,-2,1,0)
23.50	3.7864	7.8	(2,-1,-1,0)
25.21	3.5327	64.9	(1,1,-2,1)
25.37	3.5103	59.6	(1,-2,1,1)
25.39	3.5077	62.2	(2,-1,-1,1)
27.05	3.2963	8.3	(2,0,-2,0)
27.25	3.2721	17.9	(2,-2,0,0)
28.71	3.1099	28.4	(0,2,-2,1)
28.73	3.1075	10.5	(2,0,-2,1)
28.75	3.1053	2.0	(0,0,0,3)
28.92	3.0872	5.8	(2,-2,0,1)
30.27	2.9527	89.5	(1,1,-2,2)
30.41	2.9396	100.0	(1,-2,1,2)
30.42	2.9381	96.6	(2,-1,-1,2)
31.85	2.8097	19.6	(0,1,-1,3)

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Energy Properties

Formation Energy/atom

-0.75387

eV/atom

Energy/atom

-18.73963

eV/atom

Energy above Hull

0.0000

eV/atom

Uncorrected Energy

-18.7396

eV/atom

Volume/atom

16.63

Å³

c/a Ratio

1.2301

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

1.0084

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.002170

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

Al · 0.643

Element Family

PostTransition-Noble

Solute Fraction

0.357

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

0.9725

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

8.0850

J/mol·K

Ω Parameter

1.1028

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

10.812%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.3141

smaller = more stable mixing

VEC

4.400

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-9.652

kJ/mol; negative = exothermic mixing

Entropy Norm

0.7015

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (1)

aaahflpo

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-3294552

Reference Citation

The crystal structure and related material properties of CaPa3(Al3Rh)6 were obtained from the Materials Project database (MP-ID: mp-3294552, 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_CaPa3(Al3Rh)6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.57308989
_cell_length_b   7.57965730
_cell_length_c   9.31584349
_cell_angle_alpha   90.00000000
_cell_angle_beta   90.00000000
_cell_angle_gamma   119.48093196
_symmetry_Int_Tables_number   1
_chemical_formula_structural   CaPa3(Al3Rh)6
_chemical_formula_sum   'Ca1 Pa3 Al18 Rh6'
_cell_volume   465.50396291
_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  0.32851848  0.00834588  0.75000000  1.0
  Pa  Pa1  1  0.99616562  0.67367915  0.25000000  1.0
  Pa  Pa2  1  0.99838109  0.32414817  0.75000000  1.0
  Pa  Pa3  1  0.67669080  0.99733861  0.25000000  1.0
  Al  Al4  1  0.13636678  0.13224119  0.25000000  1.0
  Al  Al5  1  0.86804997  0.87193169  0.75000000  1.0
  Al  Al6  1  0.00460979  0.33617298  0.07687119  1.0
  Al  Al7  1  0.00136780  0.66792734  0.92094831  1.0
  Al  Al8  1  0.00136780  0.66792734  0.57905169  1.0
  Al  Al9  1  0.33673438  0.00370127  0.42776126  1.0
  Al  Al10  1  0.00460979  0.33617298  0.42312881  1.0
  Al  Al11  1  0.65924744  0.99508306  0.57698955  1.0
  Al  Al12  1  0.65924744  0.99508306  0.92301045  1.0
  Al  Al13  1  0.33673438  0.00370127  0.07223874  1.0
  Al  Al14  1  0.33310594  0.33224821  0.55036401  1.0
  Al  Al15  1  0.66431620  0.66351851  0.45669566  1.0
  Al  Al16  1  0.66431620  0.66351851  0.04330434  1.0
  Al  Al17  1  0.33310594  0.33224821  0.94963599  1.0
  Al  Al18  1  0.34324042  0.54900246  0.25000000  1.0
  Al  Al19  1  0.65998466  0.45131669  0.75000000  1.0
  Al  Al20  1  0.54981347  0.34410044  0.25000000  1.0
  Al  Al21  1  0.44456220  0.65286844  0.75000000  1.0
  Rh  Rh22  1  0.67678374  0.33012513  0.00150236  1.0
  Rh  Rh23  1  0.32567974  0.67083374  0.00310655  1.0
  Rh  Rh24  1  0.32567974  0.67083374  0.49689345  1.0
  Rh  Rh25  1  0.67678374  0.33012513  0.49849764  1.0
  Rh  Rh26  1  0.99727022  0.99790639  0.00315170  1.0
  Rh  Rh27  1  0.99727022  0.99790639  0.49684830  1.0

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