NaCl7
NaCl7 is an unstable, semiconducting compound of sodium and chlorine that exists primarily in theoretical or extreme-pressure research contexts.
About NaCl7
NaCl7 is a unique inorganic compound composed of sodium and chlorine. Unlike common table salt, this stoichiometry represents a highly unusual arrangement of elements that challenges standard chemical bonding expectations. Its electronic character is defined as semiconducting, marking it as a subject of interest for fundamental solid-state physics research.
Due to its position above the thermodynamic hull, this compound is considered inherently unstable under ambient conditions. Its existence is primarily documented through computational modeling and high-pressure synthesis studies, where it serves as a fascinating example of how extreme environments can force elements into unconventional structural configurations.
Key Properties
Cross-validated computational properties for NaCl7, 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.
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 NaCl7. 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 NaCl7, 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. |
|---|---|---|---|---|---|
| Pm-3 (No. 200) | cubic | 0.43 | 0.0000 | -2.493 | 2.14 |
| Pm-3 (No. 200) | cubic | 0.24 | 0.2639 | -0.220 | — |
| P1 (No. 1) | triclinic | — | — | — | 1.60 |
| Pm (No. 6) | monoclinic | — | — | — | 1.99 |
| Pmm2 (No. 25) | orthorhombic | — | — | — | 1.65 |
| Cm (No. 8) | monoclinic | — | — | — | 1.70 |
| P1 (No. 1) | triclinic | — | — | — | 1.70 |
| Pm-3 (No. 200) | cubic | — | — | — | 1.99 |
| Cm (No. 8) | monoclinic | — | — | — | 1.78 |
| Cm (No. 8) | monoclinic | — | — | — | 2.39 |
| Pmm2 (No. 25) | orthorhombic | — | — | — | 2.20 |
| Pmm2 (No. 25) | orthorhombic | — | — | — | 1.79 |
Applications
Where NaCl7 is used.
Frequently Asked Questions
Common questions about NaCl7, answered from cross-validated data.
What is NaCl7?
NaCl7 is an unstable, semiconducting compound of sodium and chlorine that exists primarily in theoretical or extreme-pressure research contexts.
What is NaCl7 used for?
What is the band gap of NaCl7?
Is NaCl7 a metal, semiconductor, or insulator?
Is NaCl7 thermodynamically stable?
What is the crystal structure of NaCl7?
What is the density of NaCl7?
How many polymorphs of NaCl7 are known?
What elements does NaCl7 contain?
Where does the data for NaCl7 come from?
How It Compares
As a highly specialized and theoretically driven material, NaCl7 does not belong to a standard family of stable salts. It stands apart from conventional ionic compounds by exhibiting a complex structural landscape that has been captured across multiple independent databases, reflecting its role as a niche subject in advanced materials exploration.
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)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
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