HC2
This chemical species is a transient radical molecule consisting of carbon and hydrogen atoms. It is primarily studied in the context of astrochemistry and high-energy combustion processes where it acts as a reactive intermediate.
CH
Overview
Key Properties
Cross-validated computational properties for HC2, 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.
2.50 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.
0.107 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.
Above hull
2 DFT sources
StructuresCount of reported calculated crystal structures for this formula, including alternate polymorphs, source databases, and observed space groups.
320
4 databases, 35 space groups
Crystallography
Reported Structures
Lowest-energy structures reported for HC2, 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. |
|---|---|---|---|---|---|
| P21/c (No. 14) | monoclinic | 2.50 | 0.1074 | -7.782 | 1.34 |
| C2/m (No. 12) | monoclinic | 0.00 | 0.1492 | -7.740 | 1.43 |
| C2 (No. 5) | Monoclinic | — | — | — | 2.04 |
| C2/m (No. 12) | Monoclinic | — | — | — | 1.43 |
| C2/m (No. 12) | Monoclinic | — | — | — | 1.47 |
| C2/m (No. 12) | Monoclinic | — | — | — | 1.44 |
| Cm (No. 8) | Monoclinic | — | — | — | 3.47 |
| Cm (No. 8) | Monoclinic | — | — | — | 2.62 |
| Cm (No. 8) | Monoclinic | — | — | — | 2.54 |
| P-3m1 (No. 164) | Trigonal | — | — | — | 3.50 |
| Cm (No. 8) | Monoclinic | — | — | — | 2.57 |
| Cm (No. 8) | Monoclinic | — | — | — | 2.23 |
Uses
Applications
Where HC2 is used.
Astrophysical researchCombustion chemistry studiesSpectroscopic analysis
Reference
Frequently Asked Questions
Common questions about HC2, answered from cross-validated data.
What is HC2?
This chemical species is a transient radical molecule consisting of carbon and hydrogen atoms. It is primarily studied in the context of astrochemistry and high-energy combustion processes where it acts as a reactive intermediate.
More questions
What is HC2 used for?
HC2 is used in astrophysical research, combustion chemistry studies, and spectroscopic analysis.
What is the band gap of HC2?
HC2 has a DFT-computed band gap of 2.50 eV across 320 reported structures.
Is HC2 a metal, semiconductor, or insulator?
With a band gap up to 2.50 eV it is a semiconductor.
Is HC2 thermodynamically stable?
HC2 has a lowest energy above hull of 0.107 eV/atom (above hull).
What is the crystal structure of HC2?
The lowest-energy reported polymorph of HC2 is monoclinic symmetry, space group P21/c (No. 14).
What is the density of HC2?
The computed density of the ground-state structure of HC2 is 1.34 g/cm³.
How many polymorphs of HC2 are known?
320 structures of HC2 are reported across 4 databases, spanning 35 distinct space groups.
What elements does HC2 contain?
HC2 contains C and H (2 elements).
Where does the data for HC2 come from?
HC2 data is cross-referenced from materials_project, mpaloe, cod.
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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