RbNb5O8

High-Entropy Materials HEA Traditional Materials TRA

MP-ID: mp-3295831 · Space group: P4/m (#83)

Materials Project API

Basic Information

Formula

RbNb5O8

MP-ID

mp-3295831

Elements

Sites

Density

6.0841

g/cm³

Volume

185.05

Å³

Cell a

6.6928

Cell b

6.6928

Cell c

4.1310

α Angle

90.00

β Angle

90.00

γ Angle

90.00

Space Group

P4/m

Point Group

4/m

Crystal System

Tetragonal

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
13.23	6.6928	50.2	(1,0,0)
18.75	4.7325	8.0	(1,1,0)
21.51	4.1310	27.1	(0,0,1)
25.34	3.5153	5.6	(1,0,1)
28.68	3.1122	92.1	(1,1,1)
29.85	2.9931	87.3	(2,1,0)
34.49	2.6003	70.0	(2,0,1)
37.09	2.4238	44.7	(2,1,1)
38.03	2.3663	2.5	(2,2,0)
42.72	2.1165	100.0	(3,1,0)
43.83	2.0655	46.9	(0,0,2)
44.11	2.0533	25.1	(2,2,1)
45.98	1.9737	4.1	(1,0,2)
48.06	1.8931	1.6	(1,1,2)
48.32	1.8836	36.5	(3,1,1)
49.08	1.8563	4.6	(3,2,0)
53.93	1.7000	31.8	(2,1,2)
54.17	1.6932	2.5	(3,2,1)
56.71	1.6233	3.5	(4,1,0)
59.40	1.5561	1.4	(2,2,2)
59.62	1.5508	11.6	(4,0,1)
61.36	1.5108	2.1	(4,1,1)
62.01	1.4966	30.8	(4,2,0)
62.87	1.4782	58.3	(3,1,2)

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Energy Properties

Formation Energy/atom

-2.45356

eV/atom

Energy/atom

-15.69510

eV/atom

Energy above Hull

0.0000

eV/atom

Uncorrected Energy

-15.6951

eV/atom

Volume/atom

13.22

Å³

c/a Ratio

0.6172

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

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

O · 0.571

Element Family

Metalloid-Nonmetal

Solute Fraction

0.429

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

0.8760

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

7.2831

J/mol·K

Ω Parameter

0.0000

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

52.725%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.9933

smaller = more stable mixing

VEC

4.143

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

0.000

kJ/mol; negative = exothermic mixing

Entropy Norm

0.7974

SS Former

Phase Tendency

Traditional Material Features

ROM Blended-Feature Radar

Rating & Classification

Tier

Score

0.575

Family

O-rich Multi-Component

Matrix Element

O · 0.571

Related Tasks

Related computation task IDs (1)

aaahfnmt

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-3295831

Reference Citation

The crystal structure and related material properties of RbNb5O8 were obtained from the Materials Project database (MP-ID: mp-3295831, 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_RbNb5O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.69282847
_cell_length_b   6.69282847
_cell_length_c   4.13103815
_cell_angle_alpha   90.00000000
_cell_angle_beta   90.00000000
_cell_angle_gamma   90.00000000
_symmetry_Int_Tables_number   1
_chemical_formula_structural   RbNb5O8
_chemical_formula_sum   'Rb1 Nb5 O8'
_cell_volume   185.04552865
_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  0.00000000  0.00000000  0.00000000  1.0
  Nb  Nb1  1  0.39158456  0.20732090  0.50000000  1.0
  Nb  Nb2  1  0.79267910  0.39158456  0.50000000  1.0
  Nb  Nb3  1  0.50000000  0.50000000  0.00000000  1.0
  Nb  Nb4  1  0.20732090  0.60841544  0.50000000  1.0
  Nb  Nb5  1  0.60841544  0.79267910  0.50000000  1.0
  O  O6  1  0.68964333  0.10166566  0.50000000  1.0
  O  O7  1  0.38811732  0.20564083  0.00000000  1.0
  O  O8  1  0.10166566  0.31035667  0.50000000  1.0
  O  O9  1  0.79435917  0.38811732  0.00000000  1.0
  O  O10  1  0.20564083  0.61188268  0.00000000  1.0
  O  O11  1  0.89833434  0.68964333  0.50000000  1.0
  O  O12  1  0.61188268  0.79435917  0.00000000  1.0
  O  O13  1  0.31035667  0.89833434  0.50000000  1.0

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