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.

BO
Crystal structure of B2O3 (trigonal, P3121 (No. 152))
Ground-state structure · Materials Project
Overview

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.

At a glance

Key Properties

Cross-validated computational properties for boron trioxide, aggregated across 4 databases.

Band Gap

4.13–8.38 eV
Range across DFT structures

Energy Above Hull

0.000 eV/atom
Best (lowest) across sources

Stability

On hull (stable)
2 DFT sources

Structures

69
4 databases, 17 space groups
Validation

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 Score

1.00 / 1.00
Trust tier: medium

Hull Spread

0.000 eV
EAH spread across sources

Sources Compared

2
jarvis, materials_project

Space Group Consensus

All match
Crystallography

Reported Structures

Lowest-energy structures reported for B2O3, ranked by energy above hull.

Space GroupCrystal SystemBand Gap (eV)E above hull (eV/atom)E/atom (eV)Density (g/cm³)
P3121 (No. 152)trigonal6.300.0000-8.4392.56
Cmc21 (No. 36)orthorhombic8.380.0056-8.4333.10
P1 (No. 1)triclinic4.130.0632-8.3751.81
P1 (No. 1)triclinic4.180.1084-8.3301.75
P1 (No. 1)triclinic4.430.1221-8.3161.59
P1 (No. 1)triclinic4.480.1286-8.3101.62
P1 (No. 1)triclinic4.230.1468-8.2921.66
Cm (No. 8)Monoclinic2.85
Pm (No. 6)Monoclinic3.83
P3m1 (No. 156)Trigonal3.87
Cmc21 (No. 36)Orthorhombic3.02
Cmc21 (No. 36)Orthorhombic3.14
Synthesis

Synthesis Routes

Literature-extracted synthesis procedures targeting B2O3.

Sol-Gel
Procedure available · ceder_solid_state
Sol-Gel
Procedure available · ceder_solid_state
Sol-Gel
Procedure available · ceder_solid_state
Sol-Gel
Procedure available · ceder_solid_state
Sol-Gel
Procedure available · ceder_solid_state
Sol-Gel
Procedure available · ceder_solid_state
Uses

Applications

Where boron trioxide is used.

borosilicate glass productionceramic glazesflux in metallurgyprecursor for boron fibersoptical glass manufacturing
Reference

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.

More questions
What is B2O3 used for?
boron trioxide (B2O3) is used in borosilicate glass production, ceramic glazes, flux in metallurgy, precursor for boron fibers, and optical glass manufacturing.
What is the band gap of B2O3?
boron trioxide (B2O3) has a DFT-computed band gap of 4.13–8.38 eV across 69 reported structures.
Is B2O3 a metal, semiconductor, or insulator?
With a wide band gap up to 8.38 eV it is an insulator / wide-band-gap material.
Is B2O3 thermodynamically stable?
Yes — boron trioxide (B2O3) sits on the convex hull (energy above hull 0 eV/atom), i.e. on hull (stable).
What is the crystal structure of B2O3?
The lowest-energy reported polymorph of boron trioxide (B2O3) is trigonal symmetry, space group P3121 (No. 152).
What is the density of B2O3?
The computed density of the ground-state structure of boron trioxide (B2O3) is 2.56 g/cm³.
How many polymorphs of B2O3 are known?
69 structures of B2O3 are reported across 4 databases, spanning 17 distinct space groups.
How is B2O3 synthesized?
Literature-reported routes for B2O3 include sol-gel (10 procedures documented).
What elements does B2O3 contain?
boron trioxide (B2O3) contains B and O (2 elements).
Where does the data for B2O3 come from?
B2O3 data is cross-referenced from materials_project, mpaloe, cod.
Comparison

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
  • materials_project — Data from the Materials Project. Cite: Jain et al., APL Materials 1, 011002 (2013).
  • mpaloe — Data from mpaloe.
  • cod — Data from the Crystallography Open Database. Cite: Grazulis et al., Nucleic Acids Res. 40, D420 (2012).

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