Ca
Calcium · Ca
Calcium is a reactive, metallic alkaline earth element that is thermodynamically stable and widely utilized in both biological systems and industrial manufacturing.
About Calcium
Calcium is a fundamental metallic element that sits at the center of structural and biological chemistry. As a thermodynamically stable material, it exists reliably on the convex hull, reflecting its natural abundance and chemical consistency. Its metallic electronic character defines its reactivity and role as a potent reducing agent in various chemical processes. The material is characterized by its high structural versatility, with numerous reported crystalline arrangements across scientific databases. This structural diversity allows calcium to serve as a critical component in alloy development and chemical synthesis, where its ability to participate in diverse bonding environments is highly valued.
Key Properties
Cross-validated computational properties for Calcium, aggregated across 6 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 Ca. 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 Ca, 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. |
|---|---|---|---|---|---|
| Im-3m (No. 229) | cubic | 0.00 | 0.0000 | 0.015 | — |
| Fm-3m (No. 225) | cubic | 0.00 | 0.0000 | 0.000 | — |
| P63/mmc (No. 194) | hexagonal | 0.00 | 0.0000 | 0.006 | — |
| Im-3m (No. 229) | cubic | 0.00 | 0.0000 | 0.014 | — |
| P63/mmc (No. 194) | hexagonal | 0.00 | 0.0000 | 0.006 | — |
| Fm-3m (No. 225) | cubic | 0.00 | 0.0000 | -0.017 | — |
| Fm-3m (No. 225) | cubic | 0.00 | 0.0000 | -7.038 | 1.53 |
| I4/mmm (No. 139) | tetragonal | 0.00 | 0.0000 | -0.017 | — |
| Fm-3m (No. 225) | cubic | 0.00 | 0.0000 | 0.000 | — |
| I4/mcm (No. 140) | tetragonal | 0.00 | 0.0000 | 0.154 | — |
| Pm-3m (No. 221) | cubic | 0.00 | 0.0000 | 0.379 | — |
| Im-3m (No. 229) | cubic | 0.00 | 0.0000 | 0.015 | — |
Applications
Where Calcium is used.
Frequently Asked Questions
Common questions about Calcium, answered from cross-validated data.
What is Ca?
Calcium is a reactive, metallic alkaline earth element that is thermodynamically stable and widely utilized in both biological systems and industrial manufacturing.
What is Ca used for?
What is the band gap of Ca?
Is Ca a metal, semiconductor, or insulator?
Is Ca thermodynamically stable?
What is the crystal structure of Ca?
How many polymorphs of Ca are known?
What elements does Ca contain?
Where does the data for Ca come from?
How It Compares
As a foundational metallic element, calcium serves as a primary reference point for reactivity and structural stability within the broader context of alkaline earth metals and metallic systems.
Data sources & attribution
- jarvis — Data from JARVIS (jarvis.nist.gov), NIST. Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020). (LicenseRef-US-Gov-PD)
- materials_project — Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013). (CC-BY-4.0)
- 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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