Navigation

HEAS Data Platform · Materials Science Database

Rb3CoO2

High-Entropy Materials HEA Traditional Materials TRA

MP-ID: mp-30194 · Space group: Pnma (#62)

Basic Information

Formula
Rb3CoO2
MP-ID
mp-30194
Elements
3
Sites
24
Density
3.9490
g/cm³
Volume
584.21
ų
Cell a
6.1836
Å
Cell b
7.6695
Å
Cell c
12.3187
Å
α Angle
90.00
°
β Angle
90.00
°
γ Angle
90.00
°
Space Group
Pnma
Point Group
mmm
Crystal System
Orthorhombic
Bravais Lattice
Orthorhombic P
Stability
Yes
Packing Fraction
0.5240

X-ray Diffraction

Diffraction Pattern
X-axis: 2θ (°); Y-axis: relative intensity; CuKa ; λ=1.5406 Å
Diffraction Peaks (Top 24)
2θd (Å)Ihkl
16.04 5.5264 2.3 (1,0,1)
19.80 4.4837 1.4 (1,1,1)
27.40 3.2554 2.7 (0,2,2)
28.33 3.1506 6.0 (1,2,1)
28.88 3.0918 16.1 (2,0,0)
28.99 3.0797 25.3 (0,0,4)
29.79 2.9988 12.3 (2,0,1)
31.05 2.8806 100.0 (1,2,2)
32.48 2.7567 6.6 (1,0,4)
34.50 2.5996 1.3 (2,1,2)
35.16 2.5527 8.4 (1,2,3)
36.37 2.4699 5.7 (2,0,3)
37.45 2.4012 1.0 (0,2,4)
38.09 2.3623 2.2 (2,2,1)
40.23 2.2418 1.6 (2,2,2)
41.38 2.1819 14.0 (2,0,4)
46.19 1.9653 1.1 (1,2,5)
47.17 1.9268 4.1 (2,0,5)
47.42 1.9174 10.4 (0,4,0)
48.19 1.8885 1.1 (1,1,6)
49.48 1.8421 1.5 (3,0,3)
50.42 1.8100 3.6 (0,2,6)
50.83 1.7961 8.9 (3,2,1)
52.55 1.7415 5.2 (3,2,2)
Get direct link

Energy Properties

Formation Energy/atom
-1.19144
eV/atom
Energy/atom
-4.51993
eV/atom
Energy above Hull
0.0000
eV/atom
Uncorrected Energy
-12.3339
eV/atom
Volume/atom
24.34
ų
c/a Ratio
-

Electronic Properties

Metallic
Metal
Band Gap
0
eV
Direct Gap
No
CBM
N/A
eV

Magnetic Properties

Magnetic
Yes
Total Mag. Moment
0.0000
μB
Mag. Ordering
AFM
Mag. Sites
4
Magnetization/Volume
0.000000
μB/ų

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)
Composition Info
Major / Matrix Element
Rb · 0.500
Element Family
Alkali-AlkEarth
Solute Fraction
0.500
Interstitial Fraction
0.000

High-Entropy Alloy Features

Composite Radar (normalized)
Element-Class Share
Mix Entropy ΔS/R
1.0114
HEA criterion (>1.0 = high entropy)
Mix Entropy ΔS
8.4088
J/mol·K
Ω Parameter
0.0000
Ω > 1.1 favors solid solution
Atomic Size Mismatch δr
50.318%
δr < 6.6% favors single-phase solid solution
Electronegativity Diff Δχ
1.1717
smaller = more stable mixing
VEC
3.333
valence electron concentration, affects phase stability
Mix Enthalpy ΔH_mix
0.000
kJ/mol; negative = exothermic mixing
Entropy Norm
0.9206
SS Former
0
Phase Tendency
IM

Traditional Material Features

ROM Blended-Feature Radar
Rating & Classification
Tier
B
Score
0.465
Family
Rb-rich Multi-Component
Matrix Element
Rb · 0.500

Related Tasks

Citation & References

Materials Project Page
https://materialsproject.org/materials/mp-30194
Reference Citation

The crystal structure and related material properties of Rb3CoO2 were obtained from the Materials Project database (MP-ID: mp-30194, 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

BibTeX
@article{Horton2025,
  author  = {Horton, Matthew K. and Huck, Patrick and Yang, Ruo Xi and Munro, Jason M. and Dwaraknath, Shyam and Ganose, Alex M. and Kingsbury, Ryan S. and Wen, Mingjian and Shen, Jimmy X. and Mathis, Tyler S. and Kaplan, Aaron D. and Berket, Karlo and Riebesell, Janosh and George, Janine and Rosen, Andrew S. and Spotte-Smith, Evan W. C. and McDermott, Matthew J. and Cohen, Orion A. and Dunn, Alex and Kuner, Matthew C. and Rignanese, Gian-Marco and Petretto, Guido and Waroquiers, David and Griffin, Sinead M. and Neaton, Jeffrey B. and Chrzan, Daryl C. and Asta, Mark and Hautier, Geoffroy and Cholia, Shreyas and Ceder, Gerbrand and Ong, Shyue Ping and Jain, Anubhav and Persson, Kristin A.},
  title   = {Accelerated data-driven materials science with the Materials Project},
  journal = {Nature Materials},
  year    = {2025},
  volume  = {24},
  number  = {10},
  pages   = {1522--1532},
  month   = {oct},
  doi     = {10.1038/s41563-025-02272-0},
  issn    = {1476-4660},
  url     = {https://doi.org/10.1038/s41563-025-02272-0},
  abstract = {The Materials Project was launched formally in 2011 to drive materials discovery forwards through high-throughput computation and open data. More than a decade later, the Materials Project has become an indispensable tool used by more than 600,000 materials researchers around the world. This Perspective describes how the Materials Project, as a data platform and a software ecosystem, has helped to shape research in data-driven materials science. We cover how sustainable software and computational methods have accelerated materials design while becoming more open source and collaborative in nature. Next, we present cases where the Materials Project was used to understand and discover functional materials. We then describe our efforts to meet the needs of an expanding user base, through technical infrastructure updates ranging from data architecture and cloud resources to interactive web applications. Finally, we discuss opportunities to better aid the research community, with the vision that more accessible and easy-to-understand materials data will result in democratized materials knowledge and an increasingly collaborative community.}
}

3D Crystal Structure Rendering

Loading 3D structure…

Style: Ball & Stick
Raw CIF Data
# generated using pymatgen
data_Rb3CoO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.18357472
_cell_length_b   7.66950849
_cell_length_c   12.31869315
_cell_angle_alpha   90.00000000
_cell_angle_beta   90.00000000
_cell_angle_gamma   90.00000000
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Rb3CoO2
_chemical_formula_sum   'Rb12 Co4 O8'
_cell_volume   584.21376165
_cell_formula_units_Z   4
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  0.78055080  0.75000000  0.89934805  1.0
  Rb  Rb1  1  0.28055080  0.25000000  0.60065195  1.0
  Rb  Rb2  1  0.21946636  0.25000000  0.10064051  1.0
  Rb  Rb3  1  0.71946636  0.75000000  0.39935949  1.0
  Rb  Rb4  1  0.31774709  0.50086868  0.86237091  1.0
  Rb  Rb5  1  0.81774709  0.49913132  0.63762909  1.0
  Rb  Rb6  1  0.68225627  0.00086298  0.13761500  1.0
  Rb  Rb7  1  0.18225627  0.99913702  0.36238500  1.0
  Rb  Rb8  1  0.68225627  0.49913702  0.13761500  1.0
  Rb  Rb9  1  0.18225627  0.50086298  0.36238500  1.0
  Rb  Rb10  1  0.31774709  0.99913132  0.86237091  1.0
  Rb  Rb11  1  0.81774709  0.00086868  0.63762909  1.0
  Co  Co12  1  0.30634667  0.75000000  0.61851300  1.0
  Co  Co13  1  0.19363920  0.75000000  0.11850128  1.0
  Co  Co14  1  0.80634667  0.25000000  0.88148700  1.0
  Co  Co15  1  0.69363920  0.25000000  0.38149872  1.0
  O  O16  1  0.58700340  0.25000000  0.97101837  1.0
  O  O17  1  0.08700340  0.75000000  0.52898163  1.0
  O  O18  1  0.41293374  0.75000000  0.02898032  1.0
  O  O19  1  0.91293374  0.25000000  0.47101968  1.0
  O  O20  1  0.01582569  0.25000000  0.78559692  1.0
  O  O21  1  0.48422542  0.25000000  0.28559374  1.0
  O  O22  1  0.51582569  0.75000000  0.71440308  1.0
  O  O23  1  0.98422542  0.75000000  0.21440626  1.0
Get direct link