Na2CoO3
Na2CoO3 is a stable, semiconducting layered oxide of sodium and cobalt used primarily in materials science research for electrochemical applications.

About Na2CoO3
Na2CoO3 is a member of the layered sodium transition-metal oxide family, characterized by its robust thermodynamic stability as it sits directly on the convex hull. This semiconducting compound represents a significant area of interest within solid-state chemistry due to its structural complexity and potential for ion mobility.
Its importance lies in the broader study of sodium-based cathode materials, where transition-metal oxides are essential for developing next-generation electrochemical storage. With numerous reported structures, it serves as a key reference point for understanding phase behavior in alkali-metal oxide systems.
Key Properties
Cross-validated computational properties for Na2CoO3, aggregated across 3 databases.
Band GapEnergy needed to move an electron from the valence band to the conduction band. Lower or zero values tend to behave more metallic; larger gaps are more insulating or semiconducting.
Energy Above HullThermodynamic distance from the most stable set of competing phases. 0 eV/atom is on the convex hull; small positive values may still be experimentally accessible.
StabilityA plain-language summary of the best reported energy-above-hull result. It reflects whether the lowest-energy structure is on, near, or far from the stability hull.
StructuresCount of reported calculated crystal structures for this formula, including alternate polymorphs, source databases, and observed space groups.
Reported Structures
Lowest-energy structures reported for Na2CoO3, ranked by energy above hull.
| Space GroupSymmetry classification of the crystal arrangement. The number is the international space-group index. | Crystal SystemBroad lattice family, such as cubic, tetragonal, monoclinic, or triclinic, derived from unit-cell symmetry. | Band Gap (eV)Electronic gap calculated for this specific reported structure, measured in electronvolts. | E above hull (eV/atom)Thermodynamic distance from the convex hull for this structure, normalized per atom. Lower is generally more stable. | E/atom (eV)Computed total energy normalized per atom. Use energy above hull, not this value alone, when comparing stability. | Density (g/cm³)Mass per relaxed crystal volume, reported in grams per cubic centimeter. |
|---|---|---|---|---|---|
| Cmc21 (No. 36) | orthorhombic | 0.00 | 0.0000 | -5.625 | 3.05 |
| C2/m (No. 12) | monoclinic | 0.00 | 0.0360 | -5.589 | 4.07 |
| P2 (No. 3) | monoclinic | 0.36 | 0.0410 | -5.584 | 3.97 |
| Cmc21 (No. 36) | orthorhombic | 0.00 | 0.0469 | -5.578 | 2.87 |
| P-1 (No. 2) | triclinic | 0.97 | 0.0470 | -5.578 | 3.66 |
| C2/c (No. 15) | monoclinic | 0.00 | 0.0496 | -5.575 | 3.84 |
| Pm (No. 6) | monoclinic | 0.43 | 0.0553 | -5.570 | 2.95 |
| C2 (No. 5) | monoclinic | 0.61 | 0.0602 | -5.565 | 3.90 |
| P1 (No. 1) | triclinic | 0.50 | 0.0641 | -5.561 | 3.84 |
| P1 (No. 1) | triclinic | 0.47 | 0.0698 | -5.555 | 3.85 |
| Cm (No. 8) | monoclinic | 0.33 | 0.0762 | -5.549 | 2.92 |
| P21/c (No. 14) | monoclinic | 0.14 | 0.0815 | -5.543 | 3.19 |
Applications
Where Na2CoO3 is used.
Frequently Asked Questions
Common questions about Na2CoO3, answered from cross-validated data.
What is Na2CoO3?
Na2CoO3 is a stable, semiconducting layered oxide of sodium and cobalt used primarily in materials science research for electrochemical applications.
What is Na2CoO3 used for?
What is the band gap of Na2CoO3?
Is Na2CoO3 a metal, semiconductor, or insulator?
Is Na2CoO3 thermodynamically stable?
What is the crystal structure of Na2CoO3?
What is the density of Na2CoO3?
How many polymorphs of Na2CoO3 are known?
What elements does Na2CoO3 contain?
Where does the data for Na2CoO3 come from?
How It Compares
Within the layered sodium transition-metal oxides class.
Within the diverse landscape of layered sodium transition-metal oxides, Na2CoO3 occupies a distinct structural niche compared to simpler analogs like NaCoO2. While many siblings in this class, such as NaFeO2 or NaMnO2, are widely recognized for their specific magnetic or electrochemical properties, Na2CoO3 offers a unique stoichiometry that differentiates its lattice configuration and electronic behavior from the more common monometallic oxides.
Related Compounds
Other Layered Sodium Transition-Metal Oxides in the database.
Data sources & attribution
- materials_project — Data from the Materials Project. Cite: Jain et al., APL Materials 1, 011002 (2013).
- mpaloe — Data from mpaloe.
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