Ca4Cu4O28P8
Ca4Cu4O28P8 has a DFT band gap of 0.03–0.69 eV across 7 reported structures in 2 space groups; its lowest-energy polymorph is monoclinic (P21/c (No. 14)). Cross-validated across 2 computational databases.
At a glance
Key Properties
Cross-validated computational properties for Ca4Cu4O28P8, aggregated across 2 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.
0.03–0.69 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)
1 DFT source
StructuresCount of reported calculated crystal structures for this formula, including alternate polymorphs, source databases, and observed space groups.
7
2 databases, 2 space groups
Crystallography
Reported Structures
Lowest-energy structures reported for Ca4Cu4O28P8, 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 | 0.69 | 0.0000 | -7.320 | 3.57 |
| P-1 (No. 2) | triclinic | 0.27 | 0.0119 | -7.308 | 3.39 |
| P-1 (No. 2) | triclinic | 0.00 | 0.0460 | -7.274 | 3.55 |
| P21/c (No. 14) | monoclinic | 0.03 | 0.0547 | -7.266 | 3.47 |
| — | — | — | — | — | 2.85 |
| — | — | — | — | — | 3.47 |
| — | — | — | — | — | 3.47 |
Reference
Frequently Asked Questions
Common questions about Ca4Cu4O28P8, answered from cross-validated data.
What is the band gap of Ca4Cu4O28P8?
Ca4Cu4O28P8 has a DFT-computed band gap of 0.03–0.69 eV across 7 reported structures.
More questions
Is Ca4Cu4O28P8 a metal, semiconductor, or insulator?
With a band gap up to 0.69 eV it is a semiconductor.
Is Ca4Cu4O28P8 thermodynamically stable?
Yes — Ca4Cu4O28P8 sits on the convex hull (energy above hull 0 eV/atom), i.e. on hull (stable).
What is the crystal structure of Ca4Cu4O28P8?
The lowest-energy reported polymorph of Ca4Cu4O28P8 is monoclinic symmetry, space group P21/c (No. 14).
What is the density of Ca4Cu4O28P8?
The computed density of the ground-state structure of Ca4Cu4O28P8 is 3.57 g/cm³.
How many polymorphs of Ca4Cu4O28P8 are known?
7 structures of Ca4Cu4O28P8 are reported across 2 databases, spanning 2 distinct space groups.
What elements does Ca4Cu4O28P8 contain?
Ca4Cu4O28P8 contains Ca, Cu, O, and P (4 elements).
Where does the data for Ca4Cu4O28P8 come from?
Ca4Cu4O28P8 data is cross-referenced from materials_project, omat24.
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Related Compounds
Other Cuprate Superconductors in the database.
Data sources & attribution
- materials_project — Data from the Materials Project. Cite: Jain et al., APL Materials 1, 011002 (2013).
- omat24 — Data from OMat24 (Meta FAIR). Cite: Barroso-Luque et al., arXiv 2410.12771 (2024).
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