B2O3
boron trioxide · boric oxide, boric anhydride
Boron trioxide is a stable, insulating oxide that is primarily used as a key ingredient in the production of specialty glasses and ceramics.
About boron trioxide
Boron trioxide is a thermodynamically stable oxide that serves as a fundamental building block in materials science. Its wide-gap insulating electronic character makes it an essential component for high-performance optical and structural glasses, where it helps lower melting temperatures and improve chemical durability.
Beyond its role in glass, this compound is a versatile precursor for synthesizing various boron-containing materials. Its structural diversity is highlighted by the high number of reported phases, reflecting its ability to accommodate different coordination environments in both crystalline and amorphous states.
Key Properties
Cross-validated computational properties for boron trioxide, aggregated across 5 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.
Cross-Source DFT Agreement
How well independent DFT databases agree on the thermodynamics of B2O3. Tight agreement means computed properties can be trusted without re-running calculations.
Agreement ScoreA normalized confidence score summarizing how closely independent DFT databases agree. Higher scores mean tighter cross-source agreement.
Hull SpreadDifference between the highest and lowest energy-above-hull values reported by comparable sources. Smaller spread means less thermodynamic disagreement.
Sources ComparedNumber and names of computational sources with comparable entries for this formula.
Space Group ConsensusWhether independent sources predict the same crystal symmetry for the lowest-energy structure.
Reported Structures
Lowest-energy structures reported for B2O3, 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. |
|---|---|---|---|---|---|
| — | — | 6.68 | 0.0000 | -2.623 | — |
| P3121 (No. 152) | trigonal | 6.54 | 0.0000 | -2.537 | — |
| P3121 (No. 152) | trigonal | 6.31 | 0.0000 | -8.439 | 2.56 |
| P3121 (No. 152) | trigonal | 6.54 | 0.0001 | -2.537 | — |
| — | — | 6.68 | 0.0008 | -2.622 | — |
| P3121 (No. 152) | trigonal | 6.54 | 0.0047 | -2.533 | — |
| P3121 (No. 152) | trigonal | 6.54 | 0.0047 | -2.533 | — |
| P3121 (No. 152) | trigonal | 6.54 | 0.0047 | -2.533 | — |
| P3121 (No. 152) | trigonal | 6.54 | 0.0047 | -2.533 | — |
| Cmc21 (No. 36) | orthorhombic | 8.38 | 0.0056 | -8.433 | 3.10 |
| — | — | — | 0.0174 | -2.606 | — |
| Cmc21 (No. 36) | orthorhombic | 8.81 | 0.0203 | -2.517 | — |
Applications
Where boron trioxide is used.
Frequently Asked Questions
Common questions about boron trioxide, answered from cross-validated data.
What is B2O3?
Boron trioxide is a stable, insulating oxide that is primarily used as a key ingredient in the production of specialty glasses and ceramics.
What is B2O3 used for?
What is the band gap of B2O3?
Is B2O3 a metal, semiconductor, or insulator?
Is B2O3 thermodynamically stable?
How many polymorphs of B2O3 are known?
What elements does B2O3 contain?
Where does the data for B2O3 come from?
How It Compares
As a foundational oxide, boron trioxide stands as a primary reference point for boron-based inorganic chemistry. It is one of the most extensively studied and utilized oxides in the field, providing a benchmark for stability and structural versatility that informs the development of more complex borate-based compounds.
Data sources & attribution
- oqmd — Data from the OQMD (oqmd.org). Cite: Saal et al., JOM 65, 1501 (2013); Kirklin et al., npj Comp. Mater. 1, 15010 (2015). (CC-BY-4.0)
- jarvis — Data from JARVIS (jarvis.nist.gov), NIST. Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020). (LicenseRef-US-Gov-PD)
- materials_project — Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013). (CC-BY-4.0)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
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