Ca4As2O

Ca4As2O is a stable, semiconducting inorganic compound composed of calcium, arsenic, and oxygen.

AsCaO
Crystal structure of Ca4As2O (tetragonal, I4/mmm (No. 139))
Ground-state structure · Materials Project
Overview

About Ca4As2O

Ca4As2O is a complex inorganic compound characterized by its semiconducting electronic nature. As a thermodynamically stable phase located on the convex hull, it represents a well-defined structural arrangement within the calcium-arsenic-oxygen system.

This material is of interest to researchers investigating novel semiconductors with specific stoichiometry. Its stability suggests potential for synthesis and further characterization in solid-state chemistry applications.

At a glance

Key Properties

Cross-validated computational properties for Ca4As2O, aggregated across 3 databases.

Band Gap

1.24–1.39 eV
Range across DFT structures · ground state: narrow gap

Energy Above Hull

0.000 eV/atom
Best (lowest) across sources

Stability

Stable
3 DFT sources

Structures

6
3 databases, 1 space group
Validation

Cross-Source DFT Agreement

How well independent DFT databases agree on the thermodynamics of Ca4As2O. Tight agreement means computed properties can be trusted without re-running calculations.

Agreement Score

1.00 / 1.00
Trust tier: high

Hull Spread

0.000 eV
EAH spread across sources

Sources Compared

3
jarvis, materials_project, oqmd

Space Group Consensus

All match
Crystallography

Reported Structures

Lowest-energy structures reported for Ca4As2O, ranked by energy above hull.

Space GroupCrystal SystemBand Gap (eV)E above hull (eV/atom)E/atom (eV)Density (g/cm³)
——1.390.0000-1.795—
I4/mmm (No. 139)tetragonal1.240.0000-1.892—
I4/mmm (No. 139)tetragonal1.210.0000-4.9973.40
——1.290.0002-1.795—
I4/mmm (No. 139)tetragonal———3.40
I4/mmm (No. 139)tetragonal———3.41
I4/mmm (No. 139)tetragonal———3.35
Uses

Applications

Where Ca4As2O is used.

Solid-state semiconductor researchMaterials science exploration
Reference

Frequently Asked Questions

Common questions about Ca4As2O, answered from cross-validated data.

What is Ca4As2O?

Ca4As2O is a stable, semiconducting inorganic compound composed of calcium, arsenic, and oxygen.

More questions
What is Ca4As2O used for?
Ca4As2O is used in solid-state semiconductor research and materials science exploration.
What is the band gap of Ca4As2O?
Ca4As2O has a DFT-computed band gap of 1.24–1.39 eV across 6 reported structures. Standard DFT underestimates band gaps, so the measured gap is typically larger.
Is Ca4As2O a metal, semiconductor, or insulator?
DFT predicts a band gap of up to 1.39 eV (a semiconductor). Measured gaps are typically larger.
Is Ca4As2O thermodynamically stable?
Yes — Ca4As2O sits on the convex hull (energy above hull 0 eV/atom), i.e. stable.
What is the crystal structure of Ca4As2O?
The reference structure of Ca4As2O is tetragonal symmetry, space group I4/mmm (No. 139).
How many polymorphs of Ca4As2O are known?
6 structures of Ca4As2O are reported across 3 databases, spanning 1 distinct space group.
What elements does Ca4As2O contain?
Ca4As2O contains As, Ca, and O (3 elements).
Where does the data for Ca4As2O come from?
Ca4As2O data is cross-referenced from oqmd, jarvis, materials_project, mpaloe.
Comparison

How It Compares

As a distinct inorganic phase, Ca4As2O occupies a specific niche in the landscape of calcium-based pnictide oxides, serving as a reference point for understanding the structural diversity and electronic behavior of materials within this chemical family.

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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