Ca9Tm(Si3H)2

High-Entropy Materials HEA

MP-ID: mp-3296443 · Space group: Cm (#8)

Materials Project API

Basic Information

Formula

Ca9Tm(Si3H)2

MP-ID

mp-3296443

Elements

Sites

Density

2.7863

g/cm³

Volume

417.28

Å³

Cell a

8.9996

Cell b

8.9996

Cell c

8.9926

α Angle

129.97

β Angle

129.97

γ Angle

73.53

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
12.28	7.2094	42.5	(1,1,-1)
13.16	6.7294	69.3	(1,0,-1)
13.16	6.7279	70.8	(1,0,0)
16.46	5.3868	24.8	(1,-1,0)
16.50	5.3724	19.8	(0,0,1)
20.58	4.3152	22.5	(2,0,-1)
20.61	4.3086	11.0	(1,1,-2)
20.62	4.3071	15.2	(1,1,0)
21.87	4.0638	20.3	(2,1,-2)
21.88	4.0628	22.2	(2,1,-1)
23.39	3.8039	19.9	(1,-1,1)
24.70	3.6047	10.4	(2,2,-2)
26.49	3.3647	6.0	(2,0,-2)
26.50	3.3640	42.3	(2,0,0)
26.90	3.3149	13.4	(2,-1,-1)
26.90	3.3147	31.6	(2,-1,0)
26.95	3.3083	27.1	(1,0,-2)
26.95	3.3078	29.5	(1,0,1)
29.82	2.9958	44.6	(3,1,-2)
29.84	2.9939	1.2	(2,2,-3)
29.85	2.9928	10.9	(2,2,-1)
32.21	2.7791	100.0	(3,0,-2)
32.21	2.7788	59.3	(3,0,-1)
32.25	2.7755	97.1	(2,1,-3)

Get direct link

Energy Properties

Formation Energy/atom

-0.61987

eV/atom

Energy/atom

-9.39868

eV/atom

Energy above Hull

0.0000

eV/atom

Uncorrected Energy

-9.3987

eV/atom

Volume/atom

23.18

Å³

c/a Ratio

0.9992

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Total Mag. Moment

1.0000

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.002400

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

Ca · 0.500

Element Family

Alkali-AlkEarth

Solute Fraction

0.500

Interstitial Fraction

0.333

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.1175

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

9.2908

J/mol·K

Ω Parameter

0.3407

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

37.938%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.4832

smaller = more stable mixing

VEC

3.167

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-33.333

kJ/mol; negative = exothermic mixing

Entropy Norm

0.8061

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (1)

aaahfokh

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-3296443

Reference Citation

The crystal structure and related material properties of Ca9Tm(Si3H)2 were obtained from the Materials Project database (MP-ID: mp-3296443, 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…

Style: Ball & Stick | Drag to rotate · Scroll to zoom · Right-click to pan

Raw CIF Data

# generated using pymatgen
data_Ca9Tm(Si3H)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.99958557
_cell_length_b   8.99958487
_cell_length_c   8.99263937
_cell_angle_alpha   129.97144787
_cell_angle_beta   129.97145232
_cell_angle_gamma   73.53353483
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ca9Tm(Si3H)2
_chemical_formula_sum   'Ca9 Tm1 Si6 H2'
_cell_volume   417.27903012
_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  0.49584485  0.50228841  0.00016421  1.0
  Ca  Ca1  1  0.00228841  0.99584485  0.00016421  1.0
  Ca  Ca2  1  0.18065989  0.68065989  0.15959161  1.0
  Ca  Ca3  1  0.01765860  0.18125248  0.49813103  1.0
  Ca  Ca4  1  0.68125248  0.51765860  0.49813103  1.0
  Ca  Ca5  1  0.48049925  0.98049925  0.16687826  1.0
  Ca  Ca6  1  0.81546400  0.31546400  0.83573892  1.0
  Ca  Ca7  1  0.98073038  0.81686421  0.49906275  1.0
  Ca  Ca8  1  0.31686421  0.48073038  0.49906275  1.0
  Tm  Tm9  1  0.52394141  0.02394141  0.83705982  1.0
  Si  Si10  1  0.25951734  0.24243268  0.99417153  1.0
  Si  Si11  1  0.74243268  0.75951734  0.99417153  1.0
  Si  Si12  1  0.88132448  0.38132448  0.26484351  1.0
  Si  Si13  1  0.10676096  0.60676096  0.71504942  1.0
  Si  Si14  1  0.38826833  0.11163957  0.50903341  1.0
  Si  Si15  1  0.61163957  0.88826833  0.50903341  1.0
  H  H16  1  0.26427339  0.76427339  0.51542553  1.0
  H  H17  1  0.75058077  0.25058077  0.50428704  1.0

Get direct link