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Rb4CO4

High-Entropy Materials HEA Traditional Materials TRA

MP-ID: mp-645300 · Space group: Amm2 (#38)

Basic Information

Formula
Rb4CO4
MP-ID
mp-645300
Elements
3
Sites
9
Density
4.1539
g/cm³
Volume
167.05
ų
Cell a
5.0849
Å
Cell b
5.0849
Å
Cell c
6.4976
Å
α Angle
90.00
°
β Angle
90.00
°
γ Angle
96.11
°
Space Group
Amm2
Point Group
mm2
Crystal System
Orthorhombic
Bravais Lattice
Orthorhombic P
Stability
No
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
13.63 6.4976 13.1 (0,0,1)
17.54 5.0560 53.5 (1,0,0)
22.28 3.9903 2.5 (1,0,1)
23.52 3.7822 1.4 (1,-1,0)
27.28 3.2688 59.1 (1,-1,1)
27.45 3.2488 1.3 (0,0,2)
29.66 3.0116 52.1 (1,1,1)
32.77 2.7332 31.7 (1,0,2)
35.51 2.5280 100.0 (2,0,0)
36.46 2.4644 78.8 (1,-1,2)
38.06 2.3641 13.0 (2,-1,0)
38.20 2.3560 9.8 (2,0,1)
38.33 2.3485 63.9 (1,1,2)
40.61 2.2216 2.1 (2,-1,1)
41.61 2.1705 9.0 (2,1,0)
41.70 2.1659 16.3 (0,0,3)
43.98 2.0587 1.3 (2,1,1)
45.56 1.9909 8.1 (1,0,3)
47.57 1.9115 7.3 (2,-1,2)
48.12 1.8911 17.9 (2,-2,0)
50.25 1.8158 3.4 (2,-2,1)
50.57 1.8048 7.1 (2,1,2)
53.96 1.6994 12.8 (2,2,0)
54.44 1.6853 2.6 (3,0,0)
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Energy Properties

Formation Energy/atom
-1.01991
eV/atom
Energy/atom
-4.68046
eV/atom
Energy above Hull
0.7474
eV/atom
Uncorrected Energy
-4.3751
eV/atom
Volume/atom
18.56
ų
c/a Ratio
-

Electronic Properties

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

Magnetic Properties

Magnetic
No
Total Mag. Moment
0.1154
μB
Mag. Ordering
NM
Mag. Sites
0
Magnetization/Volume
0.000690
μB/ų

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)
Composition Info
Major / Matrix Element
Rb · 0.444
Element Family
Alkali-AlkEarth
Solute Fraction
0.556
Interstitial Fraction
0.111

High-Entropy Alloy Features

Composite Radar (normalized)
Element-Class Share
Mix Entropy ΔS/R
0.9650
HEA criterion (>1.0 = high entropy)
Mix Entropy ΔS
8.0227
J/mol·K
Ω Parameter
0.0000
Ω > 1.1 favors solid solution
Atomic Size Mismatch δr
61.159%
δr < 6.6% favors single-phase solid solution
Electronegativity Diff Δχ
1.2421
smaller = more stable mixing
VEC
2.667
valence electron concentration, affects phase stability
Mix Enthalpy ΔH_mix
0.000
kJ/mol; negative = exothermic mixing
Entropy Norm
0.8783
SS Former
0
Phase Tendency
IM

Traditional Material Features

ROM Blended-Feature Radar
Rating & Classification
Tier
C
Score
0.250
Family
Rb-rich Multi-Component
Matrix Element
Rb · 0.444

Related Tasks

Citation & References

Materials Project Page
https://materialsproject.org/materials/mp-645300
Reference Citation

The crystal structure and related material properties of Rb4CO4 were obtained from the Materials Project database (MP-ID: mp-645300, 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_Rb4CO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.08491728
_cell_length_b   5.08491728
_cell_length_c   6.49755500
_cell_angle_alpha   90.00000000
_cell_angle_beta   90.00000000
_cell_angle_gamma   96.11393257
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Rb4CO4
_chemical_formula_sum   'Rb4 C1 O4'
_cell_volume   167.04768509
_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  0.99261900  0.00738100  0.70691600  1.0
  Rb  Rb1  1  0.99906700  0.50455700  0.00000000  1.0
  Rb  Rb2  1  0.49544300  0.00093300  0.00000000  1.0
  Rb  Rb3  1  0.99261900  0.00738100  0.29308400  1.0
  C  C4  1  0.41508500  0.58491500  0.50000000  1.0
  O  O5  1  0.51703600  0.48296400  0.69337800  1.0
  O  O6  1  0.13619200  0.52283700  0.50000000  1.0
  O  O7  1  0.47716300  0.86380800  0.50000000  1.0
  O  O8  1  0.51703600  0.48296400  0.30662200  1.0
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