InO2
InO2 is a metastable indium oxide compound that exhibits semimetallic electronic behavior, distinguishing it from the typical wide-gap oxides in its class.
About InO2
InO2 represents a distinct and structurally complex phase within the wide-bandgap oxide semiconductor family. Despite the prevalence of indium-based oxides in modern electronics, this specific stoichiometry is noted for its near-zero-gap electronic character, which deviates significantly from the insulating behavior typically associated with its class.
Due to its position above the thermodynamic stability hull, InO2 is considered a metastable phase. Its extensive documentation across multiple structural databases highlights its importance in fundamental materials research, where it serves as a critical case study for understanding the limits of indium-oxygen bonding configurations.
Key Properties
Cross-validated computational properties for InO2, aggregated across 4 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 InO2. 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 InO2, 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. |
|---|---|---|---|---|---|
| Pnnm (No. 58) | orthorhombic | 0.07 | 0.2302 | -5.650 | 6.26 |
| P4mm (No. 99) | Tetragonal | — | — | — | 6.30 |
| P3m1 (No. 156) | Trigonal | — | — | — | 3.87 |
| P3m1 (No. 156) | Trigonal | — | — | — | 4.57 |
| Cm (No. 8) | Monoclinic | — | — | — | 7.40 |
| C2/m (No. 12) | Monoclinic | — | — | — | 7.79 |
| C2/m (No. 12) | Monoclinic | — | — | — | 7.77 |
| Imm2 (No. 44) | Orthorhombic | — | — | — | 8.74 |
| Cm (No. 8) | Monoclinic | — | — | — | 5.40 |
| I41md (No. 109) | Tetragonal | — | — | — | 6.41 |
| Cm (No. 8) | Monoclinic | — | — | — | 8.78 |
| Cm (No. 8) | Monoclinic | — | — | — | 5.15 |
Applications
Where InO2 is used.
Frequently Asked Questions
Common questions about InO2, answered from cross-validated data.
What is InO2?
InO2 is a metastable indium oxide compound that exhibits semimetallic electronic behavior, distinguishing it from the typical wide-gap oxides in its class.
What is InO2 used for?
What is the band gap of InO2?
Is InO2 a metal, semiconductor, or insulator?
Is InO2 thermodynamically stable?
What is the crystal structure of InO2?
What is the density of InO2?
How many polymorphs of InO2 are known?
What elements does InO2 contain?
Where does the data for InO2 come from?
How It Compares
Within the wide-bandgap oxide semiconductors class.
Unlike the highly stable and widely utilized Ga2O3 or SnO2, which are prized for their robust wide-gap insulating properties, InO2 behaves as a near-zero-gap semimetallic material. While its sibling In2O3 is a cornerstone of transparent conductive oxide technology, InO2 remains a more elusive and less thermodynamically favored member of the indium oxide group.
Related Compounds
Other Wide-Bandgap Oxide Semiconductors 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.
- jarvis — Data from JARVIS (NIST). Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020).
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