KMgH3

High-Entropy Materials HEA Traditional Materials TRA Elasticity Data ELA

MP-ID: mp-1017580 · Space group: Pm-3m (#221)

Materials Project API

Basic Information

Formula

KMgH3

MP-ID

mp-1017580

Elements

Sites

Density

1.2637

g/cm³

Volume

87.28

Å³

Cell a

4.4359

Cell b

4.4359

Cell c

4.4359

α Angle

90.00

β Angle

90.00

γ Angle

90.00

Space Group

Pm-3m

Point Group

m-3m

Crystal System

Cubic

Bravais Lattice

Stability

Packing Fraction

0.5236

X-ray Diffraction

Diffraction Pattern

Target / Radiation

X-axis: 2θ (°); Y-axis: relative intensity; Cu Kα ; λ=1.5418 Å

Diffraction Peaks (Top 10)

2θ	d (Å)	I	hkl
20.02	4.4359	8.9	(1,0,0)
28.46	3.1366	100.0	(1,1,0)
40.68	2.2179	20.8	(2,0,0)
45.74	1.9838	2.5	(2,1,0)
50.39	1.8109	36.4	(2,1,1)
58.89	1.5683	12.1	(2,2,0)
66.68	1.4028	14.6	(3,1,0)
74.03	1.2805	3.7	(2,2,2)
81.12	1.1855	16.0	(3,2,1)
88.08	1.1090	1.7	(4,0,0)

Get direct link

Energy Properties

Formation Energy/atom

0.70299

eV/atom

Energy/atom

-1.88648

eV/atom

Energy above Hull

1.0487

eV/atom

Uncorrected Energy

-1.7791

eV/atom

Volume/atom

17.46

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

K_VRH

20.908

GPa

G_VRH

-18.751

GPa

Young's Modulus E

GPa

Poisson Ratio ν

1.140

Pugh Ratio K/G

-1.115

Vickers Hardness Est.

GPa

Ductility

Ductile

Anisotropy

-5.012

Lame λ

33.409

GPa

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

H · 0.600

Element Family

Alkali-AlkEarth

Solute Fraction

0.400

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

0.9503

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

7.9005

J/mol·K

Ω Parameter

0.0000

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

91.242%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.5772

smaller = more stable mixing

VEC

1.200

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

0.000

kJ/mol; negative = exothermic mixing

Entropy Norm

0.8650

SS Former

Phase Tendency

Traditional Material Features

ROM Blended-Feature Radar

Rating & Classification

Tier

Score

0.334

Family

H-rich Multi-Component

Matrix Element

H · 0.600

Elasticity Features

Elastic Modulus Comparison (GPa)

Elastic Features

Elastic Anisotropy A^U

-5.0120

Homogeneous Poisson ν

1.1400

Homogeneity

1.1400

Related Tasks

Related computation task IDs (2)

aaacfzbr aaadyilr

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-1017580

Reference Citation

The crystal structure and related material properties of KMgH3 were obtained from the Materials Project database (MP-ID: mp-1017580, 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_KMgH3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.43587200
_cell_length_b   4.43587200
_cell_length_c   4.43587200
_cell_angle_alpha   90.00000000
_cell_angle_beta   90.00000000
_cell_angle_gamma   90.00000000
_symmetry_Int_Tables_number   1
_chemical_formula_structural   KMgH3
_chemical_formula_sum   'K1 Mg1 H3'
_cell_volume   87.28447769
_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
  K  K0  1  0.00000000  0.00000000  0.00000000  1.0
  Mg  Mg1  1  0.50000000  0.50000000  0.50000000  1.0
  H  H2  1  0.00000000  0.00000000  0.50000000  1.0
  H  H3  1  0.00000000  0.50000000  0.00000000  1.0
  H  H4  1  0.50000000  0.00000000  0.00000000  1.0

Get direct link