CaC2
Calcium carbide · Calcium acetylide
Calcium carbide is a chemical compound primarily used in the industrial production of acetylene gas. It reacts readily with water to release flammable gas, making it a critical component in various chemical synthesis and metalworking processes.
CCa
Overview
Key Properties
Cross-validated computational properties for Calcium carbide, aggregated across 3 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.
0.65–2.86 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.
0.000 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.
On hull (stable)
2 DFT sources
StructuresCount of reported calculated crystal structures for this formula, including alternate polymorphs, source databases, and observed space groups.
94
3 databases, 21 space groups
Crystallography
Reported Structures
Lowest-energy structures reported for CaC2, 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. |
|---|---|---|---|---|---|
| C2/c (No. 15) | monoclinic | 2.04 | 0.0000 | -9.116 | 2.20 |
| C2/m (No. 12) | monoclinic | 2.34 | 0.0002 | -9.115 | 2.19 |
| I4/mmm (No. 139) | tetragonal | 1.36 | 0.0029 | -9.113 | 2.22 |
| Immm (No. 71) | orthorhombic | 2.77 | 0.0069 | -9.109 | 2.16 |
| P-1 (No. 2) | triclinic | 2.51 | 0.0246 | -9.091 | 2.18 |
| R-3m (No. 166) | trigonal | 2.77 | 0.0556 | -9.060 | 2.06 |
| Cmcm (No. 63) | orthorhombic | 0.00 | 0.0654 | -9.050 | 2.75 |
| Pnnm (No. 58) | orthorhombic | 2.86 | 0.0685 | -9.047 | 2.10 |
| R-3m (No. 166) | trigonal | 1.71 | 0.2052 | -8.910 | 2.41 |
| Immm (No. 71) | orthorhombic | 0.00 | 0.2177 | -8.898 | 3.31 |
| P6/mmm (No. 191) | hexagonal | 0.00 | 0.7448 | -8.371 | 3.81 |
| Pn-3m (No. 224) | cubic | 1.76 | 0.7644 | -8.351 | 1.89 |
Uses
Applications
Where Calcium carbide is used.
Acetylene gas productionMetal cutting and weldingSteel desulfurizationRipening of fruit
Reference
Frequently Asked Questions
Common questions about Calcium carbide, answered from cross-validated data.
What is CaC2?
Calcium carbide is a chemical compound primarily used in the industrial production of acetylene gas. It reacts readily with water to release flammable gas, making it a critical component in various chemical synthesis and metalworking processes.
More questions
What is CaC2 used for?
Calcium carbide (CaC2) is used in acetylene gas production, metal cutting and welding, steel desulfurization, and ripening of fruit.
What is the band gap of CaC2?
Calcium carbide (CaC2) has a DFT-computed band gap of 0.65–2.86 eV across 94 reported structures.
Is CaC2 a metal, semiconductor, or insulator?
With a band gap up to 2.86 eV it is a semiconductor.
Is CaC2 thermodynamically stable?
Yes — Calcium carbide (CaC2) sits on the convex hull (energy above hull 0 eV/atom), i.e. on hull (stable).
What is the crystal structure of CaC2?
The lowest-energy reported polymorph of Calcium carbide (CaC2) is monoclinic symmetry, space group C2/c (No. 15).
What is the density of CaC2?
The computed density of the ground-state structure of Calcium carbide (CaC2) is 2.20 g/cm³.
How many polymorphs of CaC2 are known?
94 structures of CaC2 are reported across 3 databases, spanning 21 distinct space groups.
What elements does CaC2 contain?
Calcium carbide (CaC2) contains C and Ca (2 elements).
Where does the data for CaC2 come from?
CaC2 data is cross-referenced from materials_project, mpaloe, jarvis.
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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