CrO
Chromium(II) oxide · Chromous oxide
Chromium(II) oxide is an inorganic compound that acts as a basic oxide of chromium. It is primarily utilized in specialized chemical research and as a precursor in the synthesis of other chromium-based materials.
Overview
Key Properties
Cross-validated computational properties for Chromium(II) oxide, 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.
0.34–1.58 eV
Range across DFT structures
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.
0.005 eV/atom
Best (lowest) across sources
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.
Near hull (likely stable)
2 DFT sources
StructuresCount of reported calculated crystal structures for this formula, including alternate polymorphs, source databases, and observed space groups.
581
4 databases, 54 space groups
Validation
Cross-Source DFT Agreement
How well independent DFT databases agree on the thermodynamics of CrO. 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.
1.00 / 1.00
Trust tier: medium
Hull SpreadDifference between the highest and lowest energy-above-hull values reported by comparable sources. Smaller spread means less thermodynamic disagreement.
0.000 eV
EAH spread across sources
Sources ComparedNumber and names of computational sources with comparable entries for this formula.
2
jarvis, materials_project
Space Group ConsensusWhether independent sources predict the same crystal symmetry for the lowest-energy structure.
All match
Crystallography
Reported Structures
Lowest-energy structures reported for CrO, 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. |
|---|---|---|---|---|---|
| P42/mmc (No. 131) | tetragonal | 0.00 | 0.0051 | -9.268 | 4.80 |
| Cccm (No. 66) | orthorhombic | 0.00 | 0.0058 | -9.267 | 4.51 |
| P-1 (No. 2) | triclinic | 0.00 | 0.0473 | -9.225 | 4.45 |
| C2/c (No. 15) | monoclinic | 1.58 | 0.0492 | -9.223 | 4.48 |
| C2/c (No. 15) | monoclinic | 0.00 | 0.0928 | -9.180 | 4.50 |
| Cccm (No. 66) | orthorhombic | 0.00 | 0.1016 | -9.171 | 4.44 |
| P2/m (No. 10) | monoclinic | 0.00 | 0.1336 | -12.394 | 4.82 |
| Pm (No. 6) | monoclinic | 0.50 | 0.1590 | -9.114 | 4.60 |
| P42/m (No. 84) | tetragonal | 0.34 | 0.1628 | -9.110 | 4.69 |
| Pmm2 (No. 25) | orthorhombic | 0.00 | 0.1713 | -9.101 | 4.34 |
| Fm-3m (No. 225) | cubic | 0.00 | 0.3675 | -8.905 | 5.12 |
| Cmcm (No. 63) | Orthorhombic | — | — | — | 5.94 |
Synthesis
Synthesis Routes
Literature-extracted synthesis procedures targeting CrO.
Sol-Gel
Procedure available · ceder_solid_state
Sol-Gel
Procedure available · ceder_solid_state
Uses
Applications
Where Chromium(II) oxide is used.
Chemical synthesisMaterials science researchCatalyst precursor
Reference
Frequently Asked Questions
Common questions about Chromium(II) oxide, answered from cross-validated data.
What is CrO?
Chromium(II) oxide is an inorganic compound that acts as a basic oxide of chromium. It is primarily utilized in specialized chemical research and as a precursor in the synthesis of other chromium-based materials.
More questions
What is CrO used for?
Chromium(II) oxide (CrO) is used in chemical synthesis, materials science research, and catalyst precursor.
What is the band gap of CrO?
Chromium(II) oxide (CrO) has a DFT-computed band gap of 0.34–1.58 eV across 581 reported structures.
Is CrO a metal, semiconductor, or insulator?
With a band gap up to 1.58 eV it is a semiconductor.
Is CrO thermodynamically stable?
Chromium(II) oxide (CrO) has a lowest energy above hull of 0.005 eV/atom (near hull (likely stable)).
What is the crystal structure of CrO?
The lowest-energy reported polymorph of Chromium(II) oxide (CrO) is tetragonal symmetry, space group P42/mmc (No. 131).
What is the density of CrO?
The computed density of the ground-state structure of Chromium(II) oxide (CrO) is 4.80 g/cm³.
How many polymorphs of CrO are known?
581 structures of CrO are reported across 4 databases, spanning 54 distinct space groups.
How is CrO synthesized?
Literature-reported routes for CrO include sol-gel (2 procedures documented).
What elements does CrO contain?
Chromium(II) oxide (CrO) contains Cr and O (2 elements).
Where does the data for CrO come from?
CrO data is cross-referenced from materials_project, mpaloe, jarvis.
Explore
Related Compounds
Other Spinel Oxide Catalysts 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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