Krypton (Kr)
noble-gasGas
Peso atomico standard
83,798 uConfigurazione elettronica
[Ar] 4s2 3d10 4p6Punto di fusione
-157,36 °CPunto di ebollizione
-153,42 °CDensità
3,733 kg/m³Stati di ossidazione
0, +1, +2Elettronegatività (Pauling)
3Energia di ionizzazione (1ª)
13,999605 eVAnno della scoperta
1898Raggio atomico
N/DDettagli
Krypton is a heavy noble gas in group 18. It is chemically very inert under ordinary conditions, monatomic, colorless, and present in air only as a minor trace constituent. Its closed electron shell makes compound formation difficult, but not impossible under strongly oxidizing or low-temperature laboratory conditions. Technologically, krypton is valued mainly for specialized lighting, gas lasers, insulating gas mixtures, and isotope applications rather than bulk chemical reactivity.
Krypton is a "noble" gas. It is characterized by its brilliant green and orange spectral lines.
The name derives from the Greek kryptos for "concealed" or "hidden". It was discovered in liquefied atmospheric air by the Scottish chemist William Ramsay and the English chemist Morris William Travers in 1898. A wavelength in the atomic spectrum of 86Kr is a fundamental standard of length.
Krypton was discovered on May 30, 1898 by Sir William Ramsay, a Scottish chemist, and Morris M. Travers, an English chemist, while studying liquefied air. Small amounts of liquid krypton remained behind after the more volatile components of liquid air had boiled away. The earth's atmosphere is about 0.0001% krypton.
From the Greek word kryptos, hidden. Discovered in 1898 by Ramsay and Travers in the residue left after liquid air had nearly boiled away. In 1960 it was internationally agreed that the fundamental unit of length, the meter, should be defined in terms of the orange-red spectral line of 86Kr. This replaced the standard meter of Paris, which was defined in terms of a bar made of a platinum-iridium alloy. In October 1983, the meter, which originally was defined as being one ten millionth of a quadrant of the earth's polar circumference, was again redefined by the International Bureau of Weights and Measures as being the length of a path traveled by light in a vacuum during a time interval of 1/299,792,458 of a second.
Pure krypton is a colorless, odorless gas at room temperature and pressure. When electrically excited at low pressure it emits a pale whitish to greenish light with strong spectral lines. Liquid and solid krypton are colorless under ordinary viewing conditions.
Krypton is used in some high-performance lamps, photographic flash tubes, and discharge lamps where its spectral output or high atomic mass is useful. Krypton-filled incandescent lamps can reduce filament evaporation compared with cheaper argon mixtures, although cost limits widespread use. Krypton fluoride excimer lasers use krypton with fluorine to generate ultraviolet light. ⁸⁵Kr has been used as a radioactive tracer and in some thickness-gauging applications, subject to regulatory control.
The high cost of obtaining krypton from the air has limited its practical applications. Krypton is used in some types of photographic flashes used in high speed photography. Some fluorescent light bulbs are filled with a mixture of krypton and argon gases. Krypton gas is also combined with other gases to make luminous signs that glow with a greenish-yellow light. In 1960, the length of the meter was defined in terms of the orange-red spectral line of krypton-86, an isotope of krypton.
Once thought to be completely inert, krypton is known to form a few compounds. Krypton difluoride (KrF2) is the easiest krypton compound to make and gram amounts of it have been produced.
For those that are curious, pictures of krypton gas and krypton plasma can be found in the Questions and Answers section of this site.
Krypton clathrates are prepared using hydroquinone and phenol. 85Kr can be used for chemical analysis by imbedding the isotope in various solids. During this process, kryptonates are formed. Kryptonate activity is sensitive to chemical reactions at the solution surface. Estimates of the concentration of reactants are therefore made possible. Krypton is used in certain photographic flash lamps for high-speed photography.
Isotopes in Forensic Science and Anthropology
85Kr (with a half-life of 10.7 years) has been used in atmospheric monitoring programs to track the effect of atomic facilities on the surrounding environment. 85Kr is co-generated with plutonium in the fuel elements of nuclear fission reactors and can be monitored at short distances (i.e. 1 to 5 km) from an area of clandestine plutonium separation from spent fuel from the nuclear reactor. The differences in 85Kr levels in the atmosphere have been used to estimate the amount of plutonium separated at weekly intervals. The production of plutonium for nuclear weapons and the output from commercial reprocessing plants have released large amounts of 85Kr into the atmosphere [283] M. B. Kalinowski, H. Sartorius, S. Uhl, W. Weiss. J. Environ. Radioact.73, 203 (2004)..
Isotopes in Geochronology
85Kr has minimal natural production in the Earth, but its concentration in the atmosphere has increased steadily because of human activities related to the nuclear industry. 85Kr enters oceans, lakes, and groundwater through equilibration of the water with air. 85Kr is produced terrestrially as a fission product of nuclear reactors and released into the atmosphere with the noble gases. It is also produced in the atmosphere via the cosmic ray neutron-activation reaction, 84Kr (n, γ) 85Kr. Thus, the 85Kr specific activity can be used to determine the time since water was isolated from the atmosphere (Fig. IUPAC.36.1). This approach provides a valuable addition to the use of tritium (3H) as an indicator of ocean circulation and groundwater age on decadal (a period of 10 consecutive years) time scales [284] SAHRA – Sustainability of Semi-Arid Hydrology and Riparian Areas. Isotopes & Hydrology-Krypton, SAHRA – Sustainability of Semi-Arid Hydrology and Riparian Areas (2014), Feb. 26; http://web.sahra.arizona.edu/programs/isotopes/krypton.html., [285] United States Geological Survey. Resources on Isotopes-Periodic Table-Krypton, U.S. Geological Survey (2014), Feb. 26; http://wwwrcamnl.wr.usgs.gov/isoig/period/kr_iig.html..
Krypton stable isotopes react in the upper atmosphere by cosmic-ray-induced spallation and neutron activation to produce radioactive 81Kr, with a half-life of approximately 2.1×105 years. In the atmosphere, 81Kr is chemically inert and has a long residence time; because of these characteristics, it is expected that 81Kr has a relatively constant and well-constrained atmospheric source. Natural cosmogenic 81Kr is incorporated from air into infiltrating groundwater and has been used to determine the age of groundwater over time scales ranging to over 106 years [286] N. C. Sturchio, X. Du, R. Purtschert, B. E. Lehmann, M. Sultan, L. J. Patterson, Z. T. Lu, P. Muller, T. Bigler, K. Bailey, T. P. O’Connor, L. Young, R. Lorenzo, R. Becker, Z. El Alfy, B. El Kaliouby, Y. Dawood, A. M. A. Abdallah. Geophys. Res. Lett.31, L05503 (2004). https://doi.org/10.1029/2003GL019234., [287] L. Lerner. Krypton-81 Isotope can Help Map Underground Waterways, Argonne National Laboratory (2014), Feb. 26; http://www.anl.gov/articles/krypton-81-isotope-can-help-map-underground-waterways., [288] B. E. Lehman, H. Oeschger, H. H. Loosli., G. S. Hurst, S. L. Allman, C. H. Chen, S. D. Kramer, R. D. Willis, N. Thonnard. J. Geophys. Res.90, 11547 (1985)., [289] W. Jiang, K. Bailey, Z. T. Lua, P. Mueller, T. P. O’Connor, C. F. Cheng, S. M. Hu, R. Purtschert, N. C. Sturchio, Y. R. Sun, W. D. Williams, G. M. Yang. Geochim. Cosmochim. Acta91, 1 (2012)..
Isotopes in Industry
85Kr has been used as the illumination element of indicator lights of appliances and can be combined with phosphors to create materials that glow in the dark. Light is created when radiation from 85Kr strikes the phosphor [98] R. Krebs. The History And Use Of Our Earth’s Chemical Elements: A Reference Guide, 2nd ed. Greenwood Press, Westport, CT (2006).. 85Kr can be used to detect container leaks by placing the radioactive gas inside a container and measuring (with a radiation detecting device) the amount of radioactive 85Kr that escapes. Because the gas is inert, Kr will not react with anything else in the container [98] R. Krebs. The History And Use Of Our Earth’s Chemical Elements: A Reference Guide, 2nd ed. Greenwood Press, Westport, CT (2006)..
Isotopes in Medicine
A patient can inhale gaseous radioactive 85Kr, which is then absorbed in the bloodstream, enabling the blood flow of the patient to be studied. Movement of the 85Kr can be tracked with a radiation detector to reveal pathways followed by the blood and to quantify blood velocity [99] World Nuclear Association. Radioisotopes in Medicine, World Nuclear Association (2014), Feb. 23; http://www.world-nuclear.org/info/inf55.html., [284] SAHRA – Sustainability of Semi-Arid Hydrology and Riparian Areas. Isotopes & Hydrology-Krypton, SAHRA – Sustainability of Semi-Arid Hydrology and Riparian Areas (2014), Feb. 26; http://web.sahra.arizona.edu/programs/isotopes/krypton.html., [290] M. J. Winter, The University of Sheffield, WebElements Ltd. Krypton, The University of Sheffield and WebElements Ltd (2014), Feb. 26; http://www.webelements.com/krypton/isotopes.html..
Krypton chemistry is limited and dominated by fluorine compounds. The best established neutral compound is krypton difluoride (KrF₂), a volatile, thermally unstable solid made by forcing krypton and fluorine into reaction under energetic conditions. KrF₂ is a powerful fluorinating and oxidizing agent and forms salts containing cations such as KrF⁺ under strongly acidic fluoride-ion-accepting conditions. No stable krypton oxides, hydrides, or ordinary salts are known under ambient conditions.
See more information at the Krypton compound page.
Stable krypton is chemically nontoxic and nonflammable, but it can displace oxygen in confined spaces and create an asphyxiation hazard without warning. Compressed krypton cylinders present ordinary high-pressure gas risks. Cryogenic liquid krypton can cause cold burns and oxygen-enrichment hazards in nearby air. Radioactive ⁸⁵Kr is a beta emitter and requires isotope-specific radiation controls; its hazard depends on activity, containment, and exposure route.
Natural krypton occurs in the atmosphere at about one part per million by volume and is produced mainly by long-term geochemical and atmospheric accumulation of noble gas isotopes. It is not biologically essential and has little chemical interaction with soils, water, or organisms. ⁸⁵Kr is released in small amounts from nuclear fuel reprocessing and reactor-related activities and disperses globally because krypton is a persistent atmospheric gas.
Commercial krypton is obtained by fractional distillation of liquefied air, usually as a by-product of large oxygen and nitrogen plants. Its very low atmospheric concentration makes separation energy-intensive compared with argon, so supply is limited and prices are sensitive to air-separation capacity and demand from lighting, laser, window-insulation, and specialty gas markets. Recycling is uncommon except in closed industrial systems or high-value gas mixtures. Substitution by argon, xenon, or other technologies is common when exact krypton properties are not required.
Krypton is present in the air to the extent of about 1 ppm. The atmosphere of Mars has been found to contain 0.3 ppm of krypton. Solid krypton is a white crystalline substance with a face-centered cubic structure which is common to all the "rare gases."
Krypton is a trace cosmic element formed mainly by neutron-capture processes in evolved stars and by explosive nucleosynthesis pathways. It is found in the atmospheres of planets and in meteorites at low abundance, often with isotope patterns that record stellar and solar-system histories. Its noble-gas character makes it useful in planetary science as a tracer of volatile retention and atmospheric loss.
- The metre was once defined using the orange-red spectral line of ⁸⁶Kr.
- Krypton is rarer in air than helium but easier to retain because it is heavier.
- KrF₂ can oxidize substances that resist many conventional oxidants.
- Krypton-filled glazing can improve insulation, but xenon is better and more expensive.
- The name comes from Greek kryptos, meaning hidden.
Immagini
Proprietà
Fisiche
- Raggio covalente
- 116 pm Confronta Raggio covalente di tutti gli elementi →
- Raggio di van der Waals
- 202 pm Confronta Raggio di van der Waals di tutti gli elementi →
- Densità
- 3,733 kg/m³ Confronta Densità di tutti gli elementi →
- Volume molare
- 0,0322 L/mol
- Fase in condizioni STP
- Gas Confronta Fase in condizioni STP di tutti gli elementi →
- Punto di fusione
- -157,36 °C Confronta Punto di fusione di tutti gli elementi →
- Punto di ebollizione
- -153,42 °C Confronta Punto di ebollizione di tutti gli elementi →
- Conducibilità termica
- 0,009 W/(m·K) Confronta Conducibilità termica di tutti gli elementi →
- Capacità termica specifica
- 0,248 J/(g·K) Confronta Capacità termica specifica di tutti gli elementi →
- Capacità termica molare
- 20,786 J/(mol·K) Confronta Capacità termica molare di tutti gli elementi →
- Struttura cristallina
- Cubica a facce centrate Confronta Struttura cristallina di tutti gli elementi →
Chimiche
- Elettronegatività (Pauling)
- 3 Confronta Elettronegatività (Pauling) di tutti gli elementi →
- Elettronegatività (Allen)
- 2,966
- Affinità elettronica
- -1 eV (valore negativo — l'atomo non dovrebbe legare un elettrone extra)
- Energia di ionizzazione (1ª)
- 13,999605 eV Confronta Energia di ionizzazione (1ª) di tutti gli elementi →
- Energia di ionizzazione (2ª)
- 24,359924 eV Confronta Energia di ionizzazione (2ª) di tutti gli elementi →
- Energia di ionizzazione (3ª)
- 35,838123 eV Confronta Energia di ionizzazione (3ª) di tutti gli elementi →
- Energia di ionizzazione (4ª)
- 50,850175 eV Confronta Energia di ionizzazione (4ª) di tutti gli elementi →
- Energia di ionizzazione (5ª)
- 64,690223 eV Confronta Energia di ionizzazione (5ª) di tutti gli elementi →
- Stati di ossidazione
- 0, +1, +2 Confronta Stati di ossidazione di tutti gli elementi →
- Elettroni di valenza
- 8 Confronta Elettroni di valenza di tutti gli elementi →
- Configurazione elettronica
- [Ar] 4s2 3d10 4p6
Termodinamiche
- Punto triplo (temperatura)
- -157,36 °C
- Punto triplo (pressione)
- 7,32e+4 Pa
- Punto critico (temperatura)
- -63,67 °C
- Punto critico (pressione)
- 5,525e+6 Pa
- Calore di fusione
- 0,01699746 eV Confronta Calore di fusione di tutti gli elementi →
- Calore di vaporizzazione
- 0,09327875 eV Confronta Calore di vaporizzazione di tutti gli elementi →
- Calore di atomizzazione
- 0 eV
Nucleari
- Protoni
- 36 Confronta Protoni di tutti gli elementi →
- Neutroni
- 48 Confronta Neutroni di tutti gli elementi →
- Isotopi noti
- 35 Confronta Isotopi noti di tutti gli elementi →
- Isotopi stabili
- 5 Confronta Isotopi stabili di tutti gli elementi →
- Isotopo più stabile
- Kr-84
- Anno della scoperta
- 1898
Abbondanza
- Abbondanza (crosta terrestre)
- 1e-4 mg/kg Confronta Abbondanza (crosta terrestre) di tutti gli elementi →
- Abbondanza (oceano)
- 2,1 × 10−4 mg/L Confronta Abbondanza (oceano) di tutti gli elementi →
Struttura cristallina
- Costante reticolare a
- 572 pm
Struttura elettronica
- Elettroni per guscio
- 2, 8, 18, 8 Confronta Elettroni per guscio di tutti gli elementi →
Identificativi
- Numero CAS
- 7439-90-9 Confronta Numero CAS di tutti gli elementi →
- Simbolo di termine
- 1S0
- InChI
- InChI=1S/Kr
- Chiave InChI
- DNNSSWSSYDEUBZ-UHFFFAOYSA-N
Configurazione elettronica Misurato
Kr: 3d¹⁰ 4s² 4p⁶[Ar] 3d¹⁰ 4s² 4p⁶1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶Modello atomico
Gli isotopi modificano il numero di neutroni, la massa e la stabilità — non la configurazione elettronica di un atomo neutro.
Modello atomico schematico, non in scala.
Impronta atomica
Spettro di emissione / assorbimento
Distribuzione isotopica
| Numero di massa | Massa atomica (u) | Abbondanza naturale | Emivita |
|---|---|---|---|
| 80 Stabile | 79,91637808 ± 0,00000075 | 2,2860% | Stabile |
| 82 Stabile | 81,91348273 ± 0,00000094 | 11,5930% | Stabile |
| 83 Stabile | 82,91412716 ± 0,00000032 | 11,5000% | Stabile |
| 84 Stabile | 83,9114977282 ± 0,0000000044 | 56,9870% | Stabile |
| 86 Stabile | 85,9106106269 ± 0,0000000041 | 17,2790% | Stabile |
Fase / Stato
Motivo: 178,4 °C sopra il punto di ebollizione (-153,42 °C)
Schema non in scala
Punti di transizione di fase
Energie di transizione
Energia necessaria per fondere 1 mol al punto di fusione
Energia necessaria per vaporizzare 1 mol al punto di ebollizione
Densità
In condizioni standard
Stimata con la legge dei gas ideali alla T attuale
Avanzate
Spettri atomici
Sono visualizzati 10 di 36. Ordinamento per carica ionica crescente.
Righe disponibili ?
| Ione | Carica | Righe totali | Probabilità di transizione | Designazioni dei livelli |
|---|---|---|---|---|
| Kr I | 0 | 862 | 184 | 862 |
| Kr II | +1 | 1178 | 20 | 1178 |
| Kr III | +2 | 877 | 0 | 877 |
| Kr IV | +3 | 485 | 0 | 485 |
| Kr V | +4 | 174 | 0 | 174 |
| Kr VI | +5 | 142 | 0 | 142 |
| Kr VII | +6 | 73 | 0 | 73 |
| Kr VIII | +7 | 177 | 0 | 177 |
| Kr IX | +8 | 125 | 0 | 125 |
| Kr X | +9 | 46 | 0 | 46 |
Livelli disponibili ?
| Ione | Carica | Livelli |
|---|---|---|
| Kr I | 0 | 528 |
| Kr II | +1 | 163 |
| Kr III | +2 | 123 |
| Kr IV | +3 | 79 |
| Kr V | +4 | 43 |
| Kr VI | +5 | 45 |
| Kr VII | +6 | 28 |
| Kr VIII | +7 | 110 |
| Kr IX | +8 | 58 |
| Kr X | +9 | 36 |
Composti
Isotopi (5)
Naturally occurring krypton contains six stable isotopes. Seventeen other unstable isotopes are recognized. The spectral lines of krypton are easily produced and some are very sharp. While krypton is generally thought of as a rare gas that normally does not combine with other elements to form compounds, it now appears that the existence of some krypton compounds can exist. Krypton difluoride has been prepared in gram quantities and can be made by several methods. A higher fluoride of krypton and a salt of an oxyacid of krypton also have been reported. Molecule-ions of ArKr+ and KrH+ have been identified and investigated, and evidence is provided for the formation of KrXe or KrXe+.
| Numero di massa | Massa atomica (u) | Abbondanza naturale | Emivita | Modalità di decadimento | |
|---|---|---|---|---|---|
| 80 Stabile | 79,91637808 ± 0,00000075 | 2,2860% ± 0,0100% | Stabile | stable | |
| 82 Stabile | 81,91348273 ± 0,00000094 | 11,5930% ± 0,0310% | Stabile | stable | |
| 83 Stabile | 82,91412716 ± 0,00000032 | 11,5000% ± 0,0190% | Stabile | stable | |
| 84 Stabile | 83,9114977282 ± 0,0000000044 | 56,9870% ± 0,0150% | Stabile | stable | |
| 86 Stabile | 85,9106106269 ± 0,0000000041 | 17,2790% ± 0,0410% | Stabile | stable |
Righe spettrali
| Lunghezza d'onda (nm) | Intensità | Stadio di ionizzazione | Tipo | Transizione | Accuratezza | Fonte | |
|---|---|---|---|---|---|---|---|
| 384.09 nm | N/D | ID 649 | emission | 3s2.3p2 3P → 3s2.3p2 3P | Misurata | NIST | |
| 392.9 nm | N/D | Kr VIII | emission | 3d10.8f 2F* → 3d10.9g 2G | Misurata | NIST | |
| 392.9 nm | N/D | Kr VIII | emission | 3d10.8f 2F* → 3d10.9g 2G | Misurata | NIST | |
| 392.9 nm | N/D | Kr VIII | emission | 3d10.8f 2F* → 3d10.9g 2G | Misurata | NIST | |
| 429.9 nm | N/D | Kr VIII | emission | 3d10.8g 2G → 3d10.9h 2H* | Misurata | NIST | |
| 429.9 nm | N/D | Kr VIII | emission | 3d10.8g 2G → 3d10.9h 2H* | Misurata | NIST | |
| 430 nm | N/D | Kr VIII | emission | 3d10.8g 2G → 3d10.9h 2H* | Misurata | NIST | |
| 433.2 nm | N/D | Kr VIII | emission | 3d10.8h 2H* → 3d10.9i 2I | Misurata | NIST | |
| 433.2 nm | N/D | Kr VIII | emission | 3d10.8h 2H* → 3d10.9i 2I | Misurata | NIST | |
| 433.2 nm | N/D | Kr VIII | emission | 3d10.8h 2H* → 3d10.9i 2I | Misurata | NIST | |
| 433.77 nm | N/D | Kr VIII | emission | 3d10.8i 2I → 3d10.9k 2K* | Misurata | NIST | |
| 433.77 nm | N/D | Kr VIII | emission | 3d10.8i 2I → 3d10.9k 2K* | Misurata | NIST | |
| 433.77 nm | N/D | Kr VIII | emission | 3d10.8i 2I → 3d10.9k 2K* | Misurata | NIST | |
| 433.81 nm | N/D | Kr VIII | emission | 3d10.8k 2K* → 3d10.9l 2L | Misurata | NIST | |
| 433.81 nm | N/D | Kr VIII | emission | 3d10.8k 2K* → 3d10.9l 2L | Misurata | NIST | |
| 433.81 nm | N/D | Kr VIII | emission | 3d10.8k 2K* → 3d10.9l 2L | Misurata | NIST | |
| 464 nm | N/D | ID 672 | emission | 1s.5s 3S → 1s.5p 3P* | Misurata | NIST | |
| 466.79 nm | N/D | Kr VIII | emission | 3d10.10m 2M* → 3d10.12n 2N | Misurata | NIST | |
| 466.79 nm | N/D | Kr VIII | emission | 3d10.10m 2M* → 3d10.12n 2N | Misurata | NIST | |
| 466.79 nm | N/D | Kr VIII | emission | 3d10.10m 2M* → 3d10.12n 2N | Misurata | NIST | |
| 510 nm | N/D | ID 672 | emission | 1s.4p 3P* → 1s.4d 3D | Misurata | NIST | |
| 563 nm | N/D | Kr VIII | emission | 3d10.8p 2P* → 3d10.8d 2D | Misurata | NIST | |
| 565.6 nm | N/D | Kr VIII | emission | 3d10.8d 2D → 3d10.9p 2P* | Misurata | NIST | |
| 568.6 nm | N/D | Kr VIII | emission | 3d10.8d 2D → 3d10.8f 2F* | Misurata | NIST | |
| 572.7 nm | N/D | Kr VIII | emission | 3d10.8d 2D → 3d10.8f 2F* | Misurata | NIST | |
| 576.1 nm | N/D | Kr VIII | emission | 3d10.8d 2D → 3d10.9p 2P* | Misurata | NIST | |
| 578.5 nm | N/D | Kr VIII | emission | 3d10.7f 2F* → 3d10.8d 2D | Misurata | NIST | |
| 580.7 nm | N/D | Kr VIII | emission | 3d10.8p 2P* → 3d10.8d 2D | Misurata | NIST | |
| 583.2 nm | N/D | Kr VIII | emission | 3d10.7f 2F* → 3d10.8d 2D | Misurata | NIST | |
| 584.9 nm | N/D | Kr VIII | emission | 3d10.8p 2P* → 3d10.8d 2D | Misurata | NIST | |
| 605.6 nm | N/D | Kr VIII | emission | 3d10.9k 2K* → 3d10.10l 2L | Misurata | NIST | |
| 605.6 nm | N/D | Kr VIII | emission | 3d10.9k 2K* → 3d10.10l 2L | Misurata | NIST | |
| 605.6 nm | N/D | Kr VIII | emission | 3d10.9k 2K* → 3d10.10l 2L | Misurata | NIST | |
| 606.6 nm | N/D | Kr VIII | emission | 3d10.9l 2L → 3d10.10m 2M* | Misurata | NIST | |
| 606.6 nm | N/D | Kr VIII | emission | 3d10.9l 2L → 3d10.10m 2M* | Misurata | NIST | |
| 606.6 nm | N/D | Kr VIII | emission | 3d10.9l 2L → 3d10.10m 2M* | Misurata | NIST | |
| 637 nm | N/D | ID 647 | emission | 3p6.3d 2D → 3p6.3d 2D | Misurata | NIST | |
| 719.57 nm | N/D | ID 674 | emission | 2p 2P* → 2s 2S | Misurata | NIST |
Proprietà estese
Raggi covalenti (dati estesi)
- Raggio covalente (Pyykkö)
- 117 pm
- Raggio covalente (Pyykkö, legame doppio)
- 121 pm
- Raggio covalente (Pyykkö, legame triplo)
- 108 pm
Raggi di van der Waals
- Bondi
- 202 pm
- Alvarez
- 207 pm
- UFF
- 414,1 pm
- MM3
- 215 pm
Raggi atomici e metallici
- Raggio atomico (Rahm)
- 212 pm
Scale di numerazione
- Mendeleev
- 115
- Pettifor
- 4
- Glawe
- 4
Scale di elettronegatività
- Ghosh
- 0
- Gunnarsson–Lundqvist
- 5
- Robles–Bartolotti
- 4
Polarizzabilità e dispersione
- Polarizzabilità dipolare
- 16,78 a.u.
- Polarizzabilità dipolare (inc.)
- 0,02 a.u.
- C₆
- 130 Ha·Bohr6
- C₆ (Gould–Bučko)
- 136 Ha·Bohr6
Affinità chimica
- Affinità protonica
- 424,6 kJ/mol
- Basicità in fase gassosa
- 402,4 kJ/mol
Proprietà dei gas nobili
| HALOGENS | KrF2 |
Transizioni di fase e allotropi
| Punto di fusione | 115,78 K |
| Punto di ebollizione | 119,73 K |
| Punto critico (temperatura) | 209,48 K |
| Punto critico (pressione) | 5,53 MPa |
| Punto triplo (temperatura) | 115,77 K |
| Punto triplo (pressione) | 73,53 kPa |
Categorie degli stati di ossidazione
Dati di riferimento avanzati
Costanti di schermaggio (8)
| n | Orbitale | σ |
|---|---|---|
| 1 | s | 0,7684 |
| 2 | p | 3,953 |
| 2 | s | 9,602 |
| 3 | d | 15,3741 |
| 3 | p | 15,5658 |
| 3 | s | 14,9673 |
| 4 | p | 26,2308 |
| 4 | s | 24,6844 |
Modalità di decadimento degli isotopi (55)
| Isotopo | Modalità | Intensità |
|---|---|---|
| 67 | 2p | 37% |
| 67 | B+ | — |
| 68 | B+ | — |
| 68 | B+p | 90% |
| 68 | p | — |
| 69 | B+ | 100% |
| 69 | B+p | 94% |
| 70 | B+ | 100% |
| 70 | B+p | 1,3% |
| 71 | B+ | 100% |
Fattori di diffusione dei raggi X (509)
| Energia (eV) | f₁ | f₂ |
|---|---|---|
| 10 | — | 0 |
| 10,1617 | — | 0 |
| 10,3261 | — | 0 |
| 10,4931 | — | 0 |
| 10,6628 | — | 0 |
| 10,8353 | — | 0 |
| 11,0106 | — | 0 |
| 11,1886 | — | 0 |
| 11,3696 | — | 0 |
| 11,5535 | — | 0 |
Dati aggiuntivi
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
1×10-4 milligrams per kilogram
Riferimenti (1)
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
2.1×10-4 milligrams per liter
Riferimenti (1)
Sources
Sources of this element.
Krypton is present in the air to the extent of about 1 ppm. The atmosphere of Mars has been found to contain 0.3 ppm of krypton. Solid krypton is a white crystalline substance with a face-centered cubic structure which is common to all the "rare gases."
Riferimenti (1)
- [6] Krypton https://periodic.lanl.gov/36.shtml
Isotopes in Forensic Science and Anthropology
Information on the use of this element's isotopes in forensic science and anthropology.
85Kr (with a half-life of 10.7 years) has been used in atmospheric monitoring programs to track the effect of atomic facilities on the surrounding environment. 85Kr is co-generated with plutonium in the fuel elements of nuclear fission reactors and can be monitored at short distances (i.e. 1 to 5 km) from an area of clandestine plutonium separation from spent fuel from the nuclear reactor. The differences in 85Kr levels in the atmosphere have been used to estimate the amount of plutonium separated at weekly intervals. The production of plutonium for nuclear weapons and the output from commercial reprocessing plants have released large amounts of 85Kr into the atmosphere [283] M. B. Kalinowski, H. Sartorius, S. Uhl, W. Weiss. J. Environ. Radioact.73, 203 (2004)..
Riferimenti (2)
- [283] M. B. Kalinowski, H. Sartorius, S. Uhl, W. Weiss. J. Environ. Radioact.73, 203 (2004).
- [4] IUPAC Periodic Table of the Elements and Isotopes (IPTEI) https://doi.org/10.1515/pac-2015-0703
Riferimenti
(9)
Data deposited in or computed by PubChem
The half-life and atomic mass data was provided by the Atomic Mass Data Center at the International Atomic Energy Agency.
Element data are cited from the Atomic weights of the elements (an IUPAC Technical Report). The IUPAC periodic table of elements can be found at https://iupac.org/what-we-do/periodic-table-of-elements/. Additional information can be found within IUPAC publication doi:10.1515/pac-2015-0703 Copyright © 2020 International Union of Pure and Applied Chemistry.
The information are cited from Pure Appl. Chem. 2018; 90(12): 1833-2092, https://doi.org/10.1515/pac-2015-0703.
Thomas Jefferson National Accelerator Facility (Jefferson Lab) is one of 17 national laboratories funded by the U.S. Department of Energy. The lab's primary mission is to conduct basic research of the atom's nucleus using the lab's unique particle accelerator, known as the Continuous Electron Beam Accelerator Facility (CEBAF). For more information visit https://www.jlab.org/
The periodic table at the LANL (Los Alamos National Laboratory) contains basic element information together with the history, source, properties, use, handling and more. The provenance data may be found from the link under the source name.
The periodic table contains NIST's critically-evaluated data on atomic properties of the elements. The provenance data that include data for atomic spectroscopy, X-ray and gamma ray, radiation dosimetry, nuclear physics, and condensed matter physics may be found from the link under the source name. Ref: https://www.nist.gov/pml/atomic-spectra-database
This section provides all form of data related to element Krypton.
The element property data was retrieved from publications.