Kr
Krypton · Noble gas
Krypton is a colorless, odorless noble gas that exists in trace amounts in the atmosphere. It is primarily utilized in specialized lighting applications due to its ability to produce a bright glow when excited by an electrical discharge.
Kr
Overview
Key Properties
Cross-validated computational properties for Krypton, aggregated across 4 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.
7.18 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)
3 DFT sources
StructuresCount of reported calculated crystal structures for this formula, including alternate polymorphs, source databases, and observed space groups.
31
4 databases, 4 space groups
Crystallography
Reported Structures
Lowest-energy structures reported for Kr, 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. |
|---|---|---|---|---|---|
| R-3m (No. 166) | trigonal | 7.17 | 0.0000 | -12.584 | 2.95 |
| P63/mmc (No. 194) | hexagonal | 7.18 | 0.0074 | -12.577 | 2.77 |
| Fm-3m (No. 225) | cubic | 7.18 | 0.0076 | -12.577 | 2.86 |
| P63/mmc (No. 194) | hexagonal | 7.15 | 0.0079 | -12.577 | 2.81 |
| Im-3m (No. 229) | cubic | 7.17 | 0.0139 | -12.571 | 2.48 |
| P63/mmc (No. 194) | Hexagonal | — | — | — | 2.16 |
| — | — | — | — | — | — |
| R-3m (No. 166) | Trigonal | — | — | — | 2.22 |
| Fm-3m (No. 225) | — | — | — | — | — |
| Im-3m (No. 229) | Cubic | — | — | — | 2.23 |
| P63/mmc (No. 194) | Hexagonal | — | — | — | 2.14 |
| P63/mmc (No. 194) | Hexagonal | — | — | — | 2.23 |
Uses
Applications
Where Krypton is used.
Fluorescent lampsFlash photographyGas discharge tubesExcimer lasersInsulated windows
Reference
Frequently Asked Questions
Common questions about Krypton, answered from cross-validated data.
What is Kr?
Krypton is a colorless, odorless noble gas that exists in trace amounts in the atmosphere. It is primarily utilized in specialized lighting applications due to its ability to produce a bright glow when excited by an electrical discharge.
More questions
What is Kr used for?
Krypton (Kr) is used in fluorescent lamps, flash photography, gas discharge tubes, excimer lasers, and insulated windows.
What is the band gap of Kr?
Krypton (Kr) has a DFT-computed band gap of 7.18 eV across 31 reported structures.
Is Kr a metal, semiconductor, or insulator?
With a wide band gap up to 7.18 eV it is an insulator / wide-band-gap material.
Is Kr thermodynamically stable?
Yes — Krypton (Kr) sits on the convex hull (energy above hull 0 eV/atom), i.e. on hull (stable).
What is the crystal structure of Kr?
The lowest-energy reported polymorph of Krypton (Kr) is trigonal symmetry, space group R-3m (No. 166).
What is the density of Kr?
The computed density of the ground-state structure of Krypton (Kr) is 2.95 g/cm³.
How many polymorphs of Kr are known?
31 structures of Kr are reported across 4 databases, spanning 4 distinct space groups.
What elements does Kr contain?
Krypton (Kr) contains Kr (1 element).
Where does the data for Kr come from?
Kr data is cross-referenced from materials_project, mpaloe, nomad, jarvis.
Data sources & attribution
- materials_project — Data from the Materials Project. Cite: Jain et al., APL Materials 1, 011002 (2013).
- mpaloe — Data from mpaloe.
- nomad — Data from NOMAD. Cite: Draxl & Scheffler, J. Phys. Mater. 2, 036001 (2019).
- jarvis — Data from JARVIS (NIST). Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020).
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