CaC2
Calcium carbide · acetylenogen
Calcium carbide is a stable, semiconducting chemical compound primarily used to generate acetylene gas for industrial welding and chemical synthesis.
About Calcium carbide
Calcium carbide is a thermodynamically stable inorganic compound that plays a foundational role in industrial chemistry. As a semiconducting material, it is recognized for its high structural diversity, with numerous reported configurations documented across material databases.
Its primary significance lies in its reactivity, particularly its ability to release acetylene gas upon contact with water. This property makes it an essential reagent in heavy industry, where it serves as a key chemical precursor for synthetic processes and metallurgical treatments.
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.
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 CaC2. 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 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 | 1.68 | 0.0000 | -0.188 | — |
| C2/m (No. 12) | monoclinic | 2.31 | 0.0002 | -9.115 | 2.19 |
| P-1 (No. 2) | triclinic | 2.46 | 0.0022 | -0.186 | — |
| I4/mmm (No. 139) | tetragonal | 1.34 | 0.0029 | -9.113 | 2.22 |
| C2/m (No. 12) | monoclinic | 2.52 | 0.0045 | -0.183 | — |
| C2/c (No. 15) | monoclinic | 2.24 | 0.0045 | -0.183 | — |
| Immm (No. 71) | orthorhombic | 2.77 | 0.0069 | -9.109 | 2.16 |
| Immm (No. 71) | orthorhombic | 2.49 | 0.0100 | -0.178 | — |
| Immm (No. 71) | orthorhombic | 2.49 | 0.0107 | -0.177 | — |
| I4/mmm (No. 139) | tetragonal | 1.44 | 0.0110 | -0.177 | — |
| P-1 (No. 2) | triclinic | 2.51 | 0.0246 | -9.091 | 2.18 |
Applications
Where Calcium carbide is used.
Frequently Asked Questions
Common questions about Calcium carbide, answered from cross-validated data.
What is CaC2?
Calcium carbide is a stable, semiconducting chemical compound primarily used to generate acetylene gas for industrial welding and chemical synthesis.
What is CaC2 used for?
What is the band gap of CaC2?
Is CaC2 a metal, semiconductor, or insulator?
Is CaC2 thermodynamically stable?
What is the crystal structure of CaC2?
What is the density of CaC2?
How many polymorphs of CaC2 are known?
What elements does CaC2 contain?
Where does the data for CaC2 come from?
How It Compares
As a prominent inorganic carbide, this material serves as a benchmark for reactivity and structural stability within its class, functioning as a primary industrial standard for acetylene generation.
Data sources & attribution
- materials_project — Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013). (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)
- 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)
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