RbMg6B

High-Entropy Materials HEA Traditional Materials TRA Elasticity Data ELA

MP-ID: mp-1017387 · Space group: Amm2 (#38)

Materials Project API

Basic Information

Formula

RbMg6B

MP-ID

mp-1017387

Elements

Sites

Density

1.9329

g/cm³

Volume

207.99

Å³

Cell a

8.3337

Cell b

8.3337

Cell c

3.4242

α Angle

90.00

β Angle

90.00

γ Angle

119.00

Space Group

Amm2

Point Group

mm2

Crystal System

Orthorhombic

Bravais Lattice

Stability

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
12.14	7.2887	51.9	(1,0,-1,0)
12.33	7.1806	8.2	(1,-1,0,0)
21.00	4.2296	24.1	(1,1,-2,0)
21.33	4.1662	34.4	(2,-1,-1,0)
24.43	3.6444	50.5	(2,0,-2,0)
24.80	3.5903	27.3	(2,-2,0,0)
26.02	3.4242	11.4	(0,0,0,1)
28.81	3.0993	44.2	(1,0,-1,1)
28.89	3.0908	48.2	(1,-1,0,1)
32.36	2.7669	41.5	(2,1,-3,0)
32.72	2.7371	44.0	(3,-1,-2,0)
32.93	2.7198	36.0	(3,-2,-1,0)
33.68	2.6614	9.4	(1,1,-2,1)
33.89	2.6454	25.8	(2,-1,-1,1)
35.99	2.4955	100.0	(2,0,-2,1)
36.25	2.4779	32.2	(2,-2,0,1)
37.00	2.4296	7.5	(3,0,-3,0)
37.58	2.3935	13.7	(3,-3,0,0)
42.27	2.1380	6.7	(3,-1,-2,1)
42.44	2.1297	15.4	(3,-2,-1,1)
42.76	2.1148	6.6	(2,2,-4,0)
43.44	2.0831	3.7	(4,-2,-2,0)
44.67	2.0286	6.5	(3,1,-4,0)
45.49	1.9938	4.2	(4,-3,-1,0)

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Energy Properties

Formation Energy/atom

0.37612

eV/atom

Energy/atom

-1.80422

eV/atom

Energy above Hull

0.3987

eV/atom

Uncorrected Energy

-1.8042

eV/atom

Volume/atom

26.00

Å³

c/a Ratio

0.4109

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

28.187

GPa

G_VRH

8.551

GPa

Young's Modulus E

23.297

GPa

Poisson Ratio ν

0.362

Pugh Ratio K/G

3.296

Vickers Hardness Est.

0.000

GPa

Ductility

Brittle

Anisotropy

-0.262

Lame λ

22.486

GPa

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

Mg · 0.750

Element Family

Alkali-AlkEarth

Solute Fraction

0.250

Interstitial Fraction

0.125

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

0.7356

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

6.1160

J/mol·K

Ω Parameter

0.5848

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

22.578%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.3094

smaller = more stable mixing

VEC

2.000

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-10.720

kJ/mol; negative = exothermic mixing

Entropy Norm

0.6696

SS Former

Phase Tendency

Traditional Material Features

ROM Blended-Feature Radar

Rating & Classification

Tier

Score

0.589

Family

Mg-based Alloy

Matrix Element

Mg · 0.750

Elasticity Features

Elastic Modulus Comparison (GPa)

Elastic Features

Elastic Anisotropy A^U

-0.2620

Homogeneous Poisson ν

0.3620

Debye Temperature

275.1

Sound Velocity

2,368.7

m/s

Homogeneity

0.3620

Related Tasks

Related computation task IDs (1)

aaadeglh

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-1017387

Reference Citation

The crystal structure and related material properties of RbMg6B were obtained from the Materials Project database (MP-ID: mp-1017387, 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_RbMg6B
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.33370725
_cell_length_b   8.33370725
_cell_length_c   3.42424100
_cell_angle_alpha   90.00000000
_cell_angle_beta   90.00000000
_cell_angle_gamma   119.00183738
_symmetry_Int_Tables_number   1
_chemical_formula_structural   RbMg6B
_chemical_formula_sum   'Rb1 Mg6 B1'
_cell_volume   207.99473519
_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
  Rb  Rb0  1  0.33956600  0.66043400  0.50000000  1.0
  Mg  Mg1  1  0.94383300  0.68771400  0.50000000  1.0
  Mg  Mg2  1  0.31228600  0.05616700  0.50000000  1.0
  Mg  Mg3  1  0.79166000  0.20834000  0.50000000  1.0
  Mg  Mg4  1  0.79252300  0.87196300  0.00000000  1.0
  Mg  Mg5  1  0.12803700  0.20747700  0.00000000  1.0
  Mg  Mg6  1  0.59505100  0.40494900  0.00000000  1.0
  B  B7  1  0.09704500  0.90295500  0.00000000  1.0

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