Mg2Nb2BiO8

High-Entropy Materials HEA

MP-ID: mp-1048411 · Space group: C2/c (#15)

Materials Project API

Basic Information

Formula

Mg2Nb2BiO8

MP-ID

mp-1048411

Elements

Sites

Density

5.6906

g/cm³

Volume

333.47

Å³

Cell a

10.7062

Cell b

10.7062

Cell c

5.3735

α Angle

87.81

β Angle

87.81

γ Angle

32.81

Space Group

C2/c

Point Group

2/m

Crystal System

Monoclinic

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
8.62	10.2623	100.0	(1,1,0)
17.28	5.1311	2.6	(2,2,0)
19.59	4.5310	31.2	(2,1,0)
22.44	3.9626	7.5	(1,0,1)
22.69	3.9184	3.9	(1,0,-1)
25.39	3.5087	95.8	(2,1,1)
26.05	3.4208	10.4	(3,3,0)
26.07	3.4186	70.5	(2,1,-1)
26.24	3.3964	21.9	(3,2,0)
29.54	3.0237	22.4	(1,-1,0)
30.68	2.9140	55.8	(3,2,1)
30.83	2.9004	10.2	(2,0,0)
31.63	2.8285	66.2	(3,2,-1)
33.38	2.6846	34.6	(0,0,2)
34.03	2.6346	32.3	(1,-1,1)
34.19	2.6229	2.4	(1,1,2)
34.43	2.6050	3.1	(3,1,0)
34.88	2.5723	8.3	(1,1,-2)
34.97	2.5656	18.3	(4,4,0)
35.00	2.5640	2.0	(2,0,1)
35.34	2.5400	4.0	(2,0,-1)
37.44	2.4022	1.5	(4,3,1)
38.09	2.3626	3.7	(3,1,1)
38.46	2.3407	4.6	(2,2,-2)

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Energy Properties

Formation Energy/atom

-2.71675

eV/atom

Energy/atom

-7.86577

eV/atom

Energy above Hull

0.1212

eV/atom

Uncorrected Energy

-7.4430

eV/atom

Volume/atom

12.83

Å³

c/a Ratio

0.5019

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

1.9991

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.005990

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

O · 0.615

Element Family

Metalloid-Nonmetal

Solute Fraction

0.385

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.0720

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

8.9127

J/mol·K

Ω Parameter

16.7373

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

47.891%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.9250

smaller = more stable mixing

VEC

3.923

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-0.341

kJ/mol; negative = exothermic mixing

Entropy Norm

0.7733

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (2)

aaachqzg aaadzfoq

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-1048411

Reference Citation

The crystal structure and related material properties of Mg2Nb2BiO8 were obtained from the Materials Project database (MP-ID: mp-1048411, 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_Mg2Nb2BiO8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.70623089
_cell_length_b   10.70623089
_cell_length_c   5.37346258
_cell_angle_alpha   87.81192737
_cell_angle_beta   87.81192737
_cell_angle_gamma   32.80958609
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Mg2Nb2BiO8
_chemical_formula_sum   'Mg4 Nb4 Bi2 O16'
_cell_volume   333.47351068
_cell_formula_units_Z   2
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
  Mg  Mg0  1  0.87808700  0.57633800  0.76339100  1.0
  Mg  Mg1  1  0.42366200  0.12191300  0.73660900  1.0
  Mg  Mg2  1  0.12191300  0.42366200  0.23660900  1.0
  Mg  Mg3  1  0.57633800  0.87808700  0.26339100  1.0
  Nb  Nb4  1  0.04421700  0.70504600  0.73055100  1.0
  Nb  Nb5  1  0.29495400  0.95578300  0.76944900  1.0
  Nb  Nb6  1  0.95578300  0.29495400  0.26944900  1.0
  Nb  Nb7  1  0.70504600  0.04421700  0.23055100  1.0
  Bi  Bi8  1  0.69884100  0.30115900  0.75000000  1.0
  Bi  Bi9  1  0.30115900  0.69884100  0.25000000  1.0
  O  O10  1  0.01164900  0.83451600  0.03508600  1.0
  O  O11  1  0.16548400  0.98835100  0.46491400  1.0
  O  O12  1  0.98835100  0.16548400  0.96491400  1.0
  O  O13  1  0.83451600  0.01164900  0.53508600  1.0
  O  O14  1  0.32735100  0.54729100  0.61476400  1.0
  O  O15  1  0.45270900  0.67264900  0.88523600  1.0
  O  O16  1  0.67264900  0.45270900  0.38523600  1.0
  O  O17  1  0.54729100  0.32735100  0.11476400  1.0
  O  O18  1  0.92324100  0.70317000  0.44056900  1.0
  O  O19  1  0.29683000  0.07675900  0.05943100  1.0
  O  O20  1  0.44806500  0.15718400  0.37165700  1.0
  O  O21  1  0.84281600  0.55193500  0.12834300  1.0
  O  O22  1  0.55193500  0.84281600  0.62834300  1.0
  O  O23  1  0.15718400  0.44806500  0.87165700  1.0
  O  O24  1  0.70317000  0.92324100  0.94056900  1.0
  O  O25  1  0.07675900  0.29683000  0.55943100  1.0

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