Ca2O3

Ca2O3 is a semiconducting calcium oxide phase that exists as a metastable material with various reported structural configurations.

CaO
Crystal structure of Ca2O3 (triclinic, P1 (No. 1))
Ground-state structure · Materials Project
Overview

About Ca2O3

Ca2O3 is a semiconducting oxide compound composed of calcium and oxygen. Despite its composition, it remains a subject of interest in materials science due to the diverse structural arrangements it can adopt under varying conditions.

This material is characterized by its position above the thermodynamic hull, suggesting it is a metastable phase. Its existence across multiple reported structures highlights the complex landscape of calcium-rich oxides and the ongoing efforts to synthesize and stabilize such unique binary compounds.

At a glance

Key Properties

Cross-validated computational properties for Ca2O3, aggregated across 3 databases.

Band Gap

0.20 eV
Range across DFT structures

Energy Above Hull

0.214 eV/atom
Best (lowest) across sources

Stability

Above hull
2 DFT sources

Structures

41
3 databases, 13 space groups
Crystallography

Reported Structures

Lowest-energy structures reported for Ca2O3, ranked by energy above hull.

Space GroupCrystal SystemBand Gap (eV)E above hull (eV/atom)E/atom (eV)Density (g/cm³)
P1 (No. 1)triclinic0.200.2142-6.2032.63
Cm (No. 8)Monoclinic1.86
Cm (No. 8)Monoclinic2.36
Cm (No. 8)Monoclinic2.46
P4mm (No. 99)Tetragonal3.04
P4mm (No. 99)Tetragonal2.93
P4mm (No. 99)Tetragonal2.83
P4mm (No. 99)Tetragonal2.87
P4mm (No. 99)Tetragonal2.95
P4mm (No. 99)Tetragonal3.02
P3m1 (No. 156)Trigonal1.91
P3m1 (No. 156)Trigonal2.51
Uses

Applications

Where Ca2O3 is used.

Fundamental materials researchSolid-state chemistry studiesComputational modeling of metastable oxides
Reference

Frequently Asked Questions

Common questions about Ca2O3, answered from cross-validated data.

What is Ca2O3?

Ca2O3 is a semiconducting calcium oxide phase that exists as a metastable material with various reported structural configurations.

More questions
What is Ca2O3 used for?
Ca2O3 is used in fundamental materials research, solid-state chemistry studies, and computational modeling of metastable oxides.
What is the band gap of Ca2O3?
Ca2O3 has a DFT-computed band gap of 0.20 eV across 41 reported structures.
Is Ca2O3 a metal, semiconductor, or insulator?
With a band gap up to 0.20 eV it is a semiconductor.
Is Ca2O3 thermodynamically stable?
Ca2O3 has a lowest energy above hull of 0.214 eV/atom (above hull).
What is the crystal structure of Ca2O3?
The lowest-energy reported polymorph of Ca2O3 is triclinic symmetry, space group P1 (No. 1).
What is the density of Ca2O3?
The computed density of the ground-state structure of Ca2O3 is 2.63 g/cm³.
How many polymorphs of Ca2O3 are known?
41 structures of Ca2O3 are reported across 3 databases, spanning 13 distinct space groups.
What elements does Ca2O3 contain?
Ca2O3 contains Ca and O (2 elements).
Where does the data for Ca2O3 come from?
Ca2O3 data is cross-referenced from materials_project, mpaloe.
Comparison

How It Compares

As a member of the calcium-oxygen binary system, Ca2O3 represents a less conventional stoichiometry compared to the more common, thermodynamically stable calcium oxides. It serves as a case study in metastable phase exploration, where researchers investigate how specific synthesis pathways might access structures that are not the ground-state configuration.

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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