Potassium (K)
alkali-metalSolid
Peso atomico standard
39,0983 uConfigurazione elettronica
[Ar] 4s1Punto di fusione
63,38 °CPunto di ebollizione
758,85 °CDensità
890 kg/m³Stati di ossidazione
−1, +1Elettronegatività (Pauling)
0,82Energia di ionizzazione (1ª)
4,340664 eVAnno della scoperta
1807Raggio atomico
220 pmDettagli
Potassium is an alkali metal and a major rock-forming and biological element. It occurs naturally only in compounds, chiefly as K⁺ in salts, feldspars, micas, and clay minerals. The metal is highly electropositive, reacts vigorously with water, and is stored away from air and moisture. In living cells, potassium is the principal intracellular cation and is central to osmotic balance and electrical signaling.
It is one of the most reactive and electropositive of metals. Except for lithium, it is the lightest known metal. It is soft, easily cut with a knife, and is silvery in appearance immediately after a fresh surface is exposed. It rapidly oxidizes in air and must be preserved in a mineral oil such as kerosene.
As with other metals of the alkali group, it decomposes in water with the evolution of hydrogen. It catches fire spontaneously on water. Potassium and its salts impart a violet color to flames.
The name derives from the English "potash" or "pot ashes" because it is found in caustic potash (KOH). The symbol K derives from the Latin kalium via the Arabic qali for alkali. It was first isolated by the British chemist Humphry Davy in 1807 from electrolysis of potash (KOH).
Although potassium is the eighth most abundant element on earth and comprises about 2.1% of the earth's crust, it is a very reactive element and is never found free in nature. Metallic potassium was first isolated by Sir Humphry Davy in 1807 through the electrolysis of molten caustic potash (KOH). A few months after discovering potassium, Davy used the same method to isolate sodium. Potassium can be obtained from the minerals sylvite (KCl), carnallite (KCl·MgCl2·6H2O), langbeinite (K2Mg2(SO4)3) and polyhalite (K2Ca2Mg(SO4)4·2H2O). These minerals are often found in ancient lake and sea beds. Caustic potash, another important source of potassium, is primarily mined in Germany, New Mexico, California and Utah. Pure potassium is a soft, waxy metal that can be easily cut with a knife. It reacts with oxygen to form potassium superoxide (KO2) and with water to form potassium hydroxide (KOH), hydrogen gas and heat. Enough heat is produced to ignite the hydrogen gas. To prevent it from reacting with the oxygen and water in the air, samples of metallic potassium are usually stored submerged in mineral oil.
From the English word, potash - pot ashes; Latin kalium, Arab qali, alkali. Discovered in 1807 by Davy, who obtained it from caustic potash (KOH); this was the first metal isolated by electrolysis.
Pure potassium is a very soft, silvery metal when freshly cut. It tarnishes rapidly in air as oxide, hydroxide, and carbonate layers form. It has a low melting point for a metal and can be cut with a knife; samples are commonly kept under dry mineral oil or inert gas.
Elemental potassium has limited direct use because sodium is cheaper and less reactive for many purposes. It is used in some laboratory reductions and in potassium-sodium alloys for heat-transfer applications where a liquid metal is useful. Most practical demand is for potassium compounds, especially fertilizers that supply plant-available K⁺. Potassium salts are also used in glass, soaps, pyrotechnics, food processing, and chemical manufacturing.
Potassium forms an alloy with sodium (NaK) that is used as a heat transfer medium in some types of nuclear reactors.
Potassium forms many important compounds. Potassium chloride (KCl) is the most common potassium compound. It is used in fertilizers, as a salt substitute and to produce other chemicals. Potassium hydroxide (KOH) is used to make soaps, detergents and drain cleaners. Potassium carbonate (KHCO3), also known as pearl ash, is used to make some types of glass and soaps and is obtained commercially as a byproduct of the production of ammonia. Potassium superoxide (KO2) can create oxygen from water vapor (H2O) and carbon dioxide (CO2) through the following reaction: 2KO2 + H2O + 2CO2 => 2KHCO3 + O2. It is used in respiratory equipment and is produced by burning potassium metal in dry air. Potassium nitrate (KNO3), also known as saltpeter or nitre, is used in fertilizers, match heads and pyrotechnics.
The greatest demand for potash has been in its use for fertilizers. Potassium is an essential constituent for plant growth and is found in most soils.
An alloy of sodium and potassium (NaK) is used as a heat-transfer medium. Many potassium salts are of utmost importance, including the hydroxide, nitrate, carbonate, chloride, chlorate, bromide, iodide, cyanide, sulfate, chromate, and dichromate.
Isotopes in Biology
The mole fraction of 40K, n(40K)/n(K), is used to study the effects of potassium in soil on the growth of plants. Plants need potassium to promote growth and reproduction, and potassium also helps plants resist drought and diseases. The mole fraction of 40K is being studied at different depths in several soil types to determine how soil properties affect the fractionation of 40K [178] R. Fujiyoshi, Y. Satake, T. Sumiyoshi. J. Radioanal. Nucl. Chem.281, 553 (2009)..
Isotopes in Geochronology
The amount ratio n(40K)/n(40Ar) is used in potassium-argon dating by geologists, archaeologists, and paleoanthropologists to determine the age of rocks. This dating method is based on the radioactive decay of 40K, having a half-life of 1.248×109 years, to 40Ar. When lava crystalizes, 40Ar can no longer escape and begins increasing in concentration in a rock (Fig. IUPAC.19.1) [179] United States Geological Survey. Geology and Geophysics, U.S. Geological Survey (2014), Feb. 25; http://geomaps.wr.usgs.gov/common/geochronology.html., [180] New Mexico Bureau of Geology & Mineral Resources. K/Ar and 40Ar/39Ar Methods, New Mexico Bureau of Geology & Mineral Resources (2014), Feb. 25; http://geoinfo.nmt.edu/labs/argon/methods/home.html..
Isotopes in Medicine
38K, which has a half-life of 7.6 min and is produced by a nuclear reaction involving 38Ar and 40Ar as targets, is a widely used blood-flow tracer. Because 38Ar is more expensive, 40Ar, which also offers many additional advantages as a target, is more commonly used to produce 38K for medical purposes [75] J. Peterson, M. McDonell, L. Haroun, F. Monette, R. D. Hildebrand, A. Taboas. Radiological and Chemical Fact Sheets to Support Health Risk Analyses for Contaminated Areas, Prepared by Argonne National Laboratory Environmental Science Division in collaboration with U.S. Department of Energy, Richland Operations Office and Chicago Operations Office (2014), Feb. 22; http://www.remm.nlm.gov/ANL_ContaminantFactSheets_All_070418.pdf., [176] K. Nagatsu, A. Kubodera, K. Suzuki. Appl. Radiat. Isot.49, 1505 (1998)., [181] P. G. Melon, C. Brihaye, C. Degueldre, M. Guillaume, R. Czichosz, P. Rigo, H. E. Kulbertus, D. Comar. J. Nucl. Med.35, 1116 (1994)..
Potassium chemistry is dominated by the +1 oxidation state and the K⁺ ion. Common compounds include potassium chloride (KCl), the main fertilizer potash salt; potassium hydroxide (KOH), a strong base used in alkaline chemistry; potassium carbonate (K₂CO₃); potassium nitrate (KNO₃), an oxidizing salt; and potassium permanganate (KMnO₄), in which potassium is only the counterion to permanganate. Potassium forms ionic halides, oxides, superoxide potassium superoxide (KO₂), and many double salts and aluminosilicates.
See more information at the Potassium compound page.
Metallic potassium is a severe fire and chemical hazard. It reacts with water to form potassium hydroxide (KOH) and hydrogen (H₂), often with enough heat to ignite the gas. Concentrated potassium hydroxide is strongly corrosive. Soluble potassium salts vary widely in hazard; ordinary dietary amounts are essential, but excessive intake or medical exposure can disturb heart rhythm. Natural potassium contains radioactive ⁴⁰K at low abundance.
Potassium is abundant in the crust and is released slowly by weathering of silicate minerals, then cycled through soils, waters, plants, and organisms as K⁺. It is not degraded, but it is redistributed by erosion, leaching, uptake, and ion exchange on clays. Potassium is an essential plant nutrient, and deficiency limits crop growth in many soils. The isotope ⁴⁰K is a natural source of background radiation.
The potassium economy is centered on potash minerals and brines rather than the free metal. Commercial products are mined or solution-mined from evaporite deposits and processed mainly into potassium chloride (KCl), with potassium sulfate (K₂SO₄) important for chloride-sensitive crops. Demand is strongly linked to agriculture, so fertilizer logistics and ore quality dominate supply. Elemental potassium is made by chemical reduction or electrochemical routes on a much smaller scale and is not a bulk commodity comparable with sodium.
The metal is the seventh most abundant and makes up about 2.4% by weight of the earth's crust. Most potassium minerals are insoluble and the metal is obtained from them only with great difficulty.
Certain minerals, however, such as sylvite, carnallite, langbeinite, and polyhalite are found in ancient lake and sea beds and form rather extensive deposits from which potassium and its salts can readily be obtained. Potash is mined in Germany, New Mexico, California, Utah, and elsewhere. Large deposits of potash, found at a depth of some 3000 ft in Saskatchewan, promise to be important in coming years.
Potassium is also found in the ocean, but is present only in relatively small amounts, compared to sodium.
Potassium is produced in stellar nucleosynthesis and supernova-related processes but is far less abundant cosmically than lighter elements such as sodium, magnesium, and silicon. In rocky planets it behaves as a moderately incompatible lithophile element, concentrating in crustal rocks and evolved magmas. Radioactive ⁴⁰K contributed heat to early planetary interiors and remains important in geochronology.
- The chemical symbol K comes from kalium, a Neo-Latin name derived from alkali sources.
- Potassium metal is less dense than water, although contact with water is violently reactive.
- Potassium chloride can be purple or reddish as a mineral because of impurities or radiation-induced color centers.
- Potassium-argon dating depends on the decay of ⁴⁰K to ⁴⁰Ar trapped in minerals.
- Potassium superoxide (KO₂) has been used in breathing equipment because it reacts with CO₂ and moisture to release O₂.
Immagini
Proprietà
Fisiche
- Raggio atomico (empirico)
- 220 pm Confronta Raggio atomico (empirico) di tutti gli elementi →
- Raggio covalente
- 203 pm Confronta Raggio covalente di tutti gli elementi →
- Raggio di van der Waals
- 275 pm Confronta Raggio di van der Waals di tutti gli elementi →
- Raggio metallico
- 203 pm Confronta Raggio metallico di tutti gli elementi →
- Densità
- 890 kg/m³ Confronta Densità di tutti gli elementi →
- Volume molare
- 0,0453 L/mol
- Fase in condizioni STP
- Solido Confronta Fase in condizioni STP di tutti gli elementi →
- Punto di fusione
- 63,38 °C Confronta Punto di fusione di tutti gli elementi →
- Punto di ebollizione
- 758,85 °C Confronta Punto di ebollizione di tutti gli elementi →
- Conducibilità termica
- 79 W/(m·K) Confronta Conducibilità termica di tutti gli elementi →
- Capacità termica specifica
- 0,757 J/(g·K) Confronta Capacità termica specifica di tutti gli elementi →
- Capacità termica molare
- 29,6 J/(mol·K) Confronta Capacità termica molare di tutti gli elementi →
- Struttura cristallina
- Cubica a corpo centrato Confronta Struttura cristallina di tutti gli elementi →
Chimiche
- Elettronegatività (Pauling)
- 0,82 Confronta Elettronegatività (Pauling) di tutti gli elementi →
- Elettronegatività (Allen)
- 0,734
- Affinità elettronica
- 0,5014 eV
- Energia di ionizzazione (1ª)
- 4,340664 eV Confronta Energia di ionizzazione (1ª) di tutti gli elementi →
- Energia di ionizzazione (2ª)
- 31,625109 eV Confronta Energia di ionizzazione (2ª) di tutti gli elementi →
- Energia di ionizzazione (3ª)
- 45,803258 eV Confronta Energia di ionizzazione (3ª) di tutti gli elementi →
- Energia di ionizzazione (4ª)
- 60,91721 eV Confronta Energia di ionizzazione (4ª) di tutti gli elementi →
- Energia di ionizzazione (5ª)
- 82,660285 eV Confronta Energia di ionizzazione (5ª) di tutti gli elementi →
- Stati di ossidazione
- −1, +1 Confronta Stati di ossidazione di tutti gli elementi →
- Elettroni di valenza
- 1 Confronta Elettroni di valenza di tutti gli elementi →
- Configurazione elettronica
- [Ar] 4s1
Termodinamiche
- Punto critico (temperatura)
- 1950 °C
- Punto critico (pressione)
- 1,6e+7 Pa
- Calore di fusione
- 0,02414883 eV Confronta Calore di fusione di tutti gli elementi →
- Calore di vaporizzazione
- 0,79701508 eV Confronta Calore di vaporizzazione di tutti gli elementi →
- Calore di sublimazione
- 0,92449604 eV
- Calore di atomizzazione
- 0,92449604 eV
- Entalpia di atomizzazione
- 0,92242317 eV
Nucleari
- Protoni
- 19 Confronta Protoni di tutti gli elementi →
- Neutroni
- 20 Confronta Neutroni di tutti gli elementi →
- Isotopi noti
- 29 Confronta Isotopi noti di tutti gli elementi →
- Isotopi stabili
- 2 Confronta Isotopi stabili di tutti gli elementi →
- Isotopo più stabile
- K-39
- Anno della scoperta
- 1807
Abbondanza
- Abbondanza (crosta terrestre)
- 2,09e+4 mg/kg Confronta Abbondanza (crosta terrestre) di tutti gli elementi →
- Abbondanza (oceano)
- 399 mg/L Confronta Abbondanza (oceano) di tutti gli elementi →
Struttura cristallina
- Costante reticolare a
- 523 pm
Struttura elettronica
- Elettroni per guscio
- 2, 8, 8, 1 Confronta Elettroni per guscio di tutti gli elementi →
Identificativi
- Numero CAS
- 7440-09-7 Confronta Numero CAS di tutti gli elementi →
- Simbolo di termine
- 2S1/2
- InChI
- InChI=1S/K
- Chiave InChI
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N
Configurazione elettronica Misurato
K: 4s¹[Ar] 4s¹1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹Modello 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 |
|---|---|---|---|
| 39 Stabile | 38,9637064864 ± 0,0000000049 | 93,2581% | Stabile |
| 41 Stabile | 40,9618252579 ± 0,0000000041 | 6,7302% | Stabile |
Fase / Stato
Motivo: 38,4 °C sotto il punto di fusione (63,38 °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
Energia necessaria per sublimare 1 mol al punto di sublimazione
Densità
In condizioni standard
In condizioni standard
Avanzate
Spettri atomici
Sono visualizzati 10 di 22. Ordinamento per carica ionica crescente.
Livelli disponibili ?
| Ione | Carica | Livelli |
|---|---|---|
| 41K I Isotopo | 0 | 8 |
| 40K I Isotopo | 0 | 3 |
| 39K I Isotopo | 0 | 123 |
| K I | 0 | 299 |
| K II | +1 | 97 |
| K III | +2 | 40 |
| K IV | +3 | 38 |
| K V | +4 | 40 |
| K VI | +5 | 28 |
| K VII | +6 | 81 |
Raggi ionici
| Carica | Coordinazione | Spin | Raggio |
|---|---|---|---|
| +1 | 4 | N/D | 137 pm |
| +1 | 6 | N/D | 138 pm |
| +1 | 7 | N/D | 146 pm |
| +1 | 8 | N/D | 151 pm |
| +1 | 9 | N/D | 155 pm |
| +1 | 10 | N/D | 159 pm |
| +1 | 12 | N/D | 164 pm |
Composti
Isotopi (2)
Seventeen isotopes of potassium are known. Ordinary potassium is composed of three isotopes, one of which is 40°K (0.0118%), a radioactive isotope with a half-life of 1.28 x 109 years.
| Numero di massa | Massa atomica (u) | Abbondanza naturale | Emivita | Modalità di decadimento | |
|---|---|---|---|---|---|
| 39 Stabile | 38,9637064864 ± 0,0000000049 | 93,2581% ± 0,0044% | Stabile | stable | |
| 41 Stabile | 40,9618252579 ± 0,0000000041 | 6,7302% ± 0,0044% | Stabile | stable |
Righe spettrali
Sono visualizzati 50 di 141. Per impostazione predefinita sono mostrate soltanto le righe spettrali con intensità misurata.
| Lunghezza d'onda (nm) | Intensità | Stadio di ionizzazione | Tipo | Transizione | Accuratezza | Fonte | |
|---|---|---|---|---|---|---|---|
| 693.8764 nm | 20 | K I | emission | 3p6.4p 2P* → 3p6.6s 2S | Misurata | NIST | |
| 691.10815 nm | 19 | K I | emission | 3p6.4p 2P* → 3p6.6s 2S | Misurata | NIST | |
| 404.41422 nm | 18 | K I | emission | 3p6.4s 2S → 3p6.5p 2P* | Misurata | NIST | |
| 404.72132 nm | 17 | K I | emission | 3p6.4s 2S → 3p6.5p 2P* | Misurata | NIST | |
| 580.17662 nm | 17 | K I | emission | 3p6.4p 2P* → 3p6.7s 2S | Misurata | NIST | |
| 583.18899 nm | 17 | K I | emission | 3p6.4p 2P* → 3p6.5d 2D | Misurata | NIST | |
| 578.23999 nm | 16 | K I | emission | 3p6.4p 2P* → 3p6.7s 2S | Misurata | NIST | |
| 581.21521 nm | 15 | K I | emission | 3p6.4p 2P* → 3p6.5d 2D | Misurata | NIST | |
| 535.95761 nm | 14 | K I | emission | 3p6.4p 2P* → 3p6.6d 2D | Misurata | NIST | |
| 533.96873 nm | 13 | K I | emission | 3p6.4p 2P* → 3p6.8s 2S | Misurata | NIST | |
| 511.225448 nm | 12 | K I | emission | 3p6.4p 2P* → 3p6.7d 2D | Misurata | NIST | |
| 532.32786 nm | 12 | K I | emission | 3p6.4p 2P* → 3p6.8s 2S | Misurata | NIST | |
| 534.29693 nm | 12 | K I | emission | 3p6.4p 2P* → 3p6.6d 2D | Misurata | NIST | |
| 693.62861 nm | 12 | K I | emission | 3p6.4p 2P* → 3p6.4d 2D | Misurata | NIST | |
| 696.46903 nm | 12 | K I | emission | 3p6.4p 2P* → 3p6.4d 2D | Misurata | NIST | |
| 464.23725 nm | 11 | K I | emission | 3p6.4s 2S → 3p6.3d 2D | Misurata | NIST | |
| 509.717137 nm | 11 | K I | emission | 3p6.4p 2P* → 3p6.7d 2D | Misurata | NIST | |
| 509.920005 nm | 11 | K I | emission | 3p6.4p 2P* → 3p6.9s 2S | Misurata | NIST | |
| 464.1875 nm | 10 | K I | emission | 3p6.4s 2S → 3p6.3d 2D | Misurata | NIST | |
| 496.503213 nm | 10 | K I | emission | 3p6.4p 2P* → 3p6.8d 2D | Misurata | NIST | |
| 508.423399 nm | 10 | K I | emission | 3p6.4p 2P* → 3p6.9s 2S | Misurata | NIST | |
| 482.924 nm | 9 | K II | emission | 3p5.4s 3P* → 3p5.4p 3S | Misurata | NIST | |
| 486.975897 nm | 9 | K I | emission | 3p6.4p 2P* → 3p6.9d 2D | Misurata | NIST | |
| 495.081801 nm | 9 | K I | emission | 3p6.4p 2P* → 3p6.8d 2D | Misurata | NIST | |
| 495.614802 nm | 9 | K I | emission | 3p6.4p 2P* → 3p6.10s 2S | Misurata | NIST | |
| 389.7896 nm | 8 | K II | emission | 3p5.4s 3P* → 3p5.4p 1D | Misurata | NIST | |
| 418.6232 nm | 8 | K II | emission | 3p5.4s 3P* → 3p5.4p 3D | Misurata | NIST | |
| 460.849 nm | 8 | K II | emission | 3p5.4s 1P* → 3p5.4p 1D | Misurata | NIST | |
| 480.43395 nm | 8 | K I | emission | 3p6.4p 2P* → 3p6.10d 2D | Misurata | NIST | |
| 485.609209 nm | 8 | K I | emission | 3p6.4p 2P* → 3p6.9d 2D | Misurata | NIST | |
| 486.348075 nm | 8 | K I | emission | 3p6.4p 2P* → 3p6.11s 2S | Misurata | NIST | |
| 500.564 nm | 8 | K II | emission | 3p5.4s 3P* → 3p5.4p 3S | Misurata | NIST | |
| 612.028 nm | 8 | K II | emission | 3p5.3d 3F* → 3p5.4p 3D | Misurata | NIST | |
| 381.7547 nm | 7 | K II | emission | 3p5.4p 3D → 3p5.(2P*<3/2>).5s 2[3/2]* | Misurata | NIST | |
| 400.122 nm | 7 | K II | emission | 3p5.4s 3P* → 3p5.4p 3P | Misurata | NIST | |
| 413.4705 nm | 7 | K II | emission | 3p5.4s 3P* → 3p5.4p 3D | Misurata | NIST | |
| 422.296 nm | 7 | K II | emission | 3p5.4s 1P* → 3p5.4p 3P | Misurata | NIST | |
| 422.566 nm | 7 | K II | emission | 3p5.3d 3P* → 3p5.4p 1D | Misurata | NIST | |
| 426.334 nm | 7 | K II | emission | 3p5.4s 3P* → 3p5.4p 3D | Misurata | NIST | |
| 430.498 nm | 7 | K II | emission | 3p5.3d 3P* → 3p5.4p 1D | Misurata | NIST | |
| 430.911 nm | 7 | K II | emission | 3p5.4s 1P* → 3p5.4p 3P | Misurata | NIST | |
| 438.816 nm | 7 | K II | emission | 3p5.4s 1P* → 3p5.4p 1P | Misurata | NIST | |
| 475.737719 nm | 7 | K I | emission | 3p6.4p 2P* → 3p6.11d 2D | Misurata | NIST | |
| 479.104132 nm | 7 | K I | emission | 3p6.4p 2P* → 3p6.10d 2D | Misurata | NIST | |
| 484.98645 nm | 7 | K I | emission | 3p6.4p 2P* → 3p6.11s 2S | Misurata | NIST | |
| 505.625 nm | 7 | K II | emission | 3p5.3d 3P* → 3p5.4p 3S | Misurata | NIST | |
| 630.728 nm | 7 | K II | emission | 3p5.3d 3F* → 3p5.4p 3D | Misurata | NIST | |
| 696.41712 nm | 7 | K I | emission | 3p6.4p 2P* → 3p6.4d 2D | Misurata | NIST | |
| 380.0162 nm | 6 | K II | emission | 3p5.4p 3D → 3p5.(2P*<3/2>).5s 2[3/2]* | Misurata | NIST | |
| 381.657 nm | 6 | K II | emission | 3p5.4p 3P → 3p5.4d 3P* | Misurata | NIST |
Proprietà estese
Raggi covalenti (dati estesi)
- Raggio covalente (Pyykkö)
- 196 pm
- Raggio covalente (Pyykkö, legame doppio)
- 193 pm
- Raggio covalente (Bragg)
- 207 pm
Raggi di van der Waals
- Bondi
- 275 pm
- Batsanov
- 280 pm
- Alvarez
- 273 pm
- UFF
- 381,2 pm
- MM3
- 309 pm
Raggi atomici e metallici
- Raggio atomico (Rahm)
- 234 pm
- Raggio metallico (C12)
- 235 pm
Scale di numerazione
- Mendeleev
- 3
- Pettifor
- 10
- Glawe
- 10
Scale di elettronegatività
- Ghosh
- 0
- Miedema
- 2
- Gunnarsson–Lundqvist
- 2
- Robles–Bartolotti
- 1
Polarizzabilità e dispersione
- Polarizzabilità dipolare
- 289,7 a.u.
- Polarizzabilità dipolare (inc.)
- 0,3 a.u.
- C₆
- 3923 Ha·Bohr6
- C₆ (Gould–Bučko)
- 3910 Ha·Bohr6
Parametri di Miedema
- Volume molare di Miedema
- 45,63 cm3/mol
- Densità elettronica di Miedema
- 0
Rischio di approvvigionamento ed economia
- Concentrazione della produzione
- 21
- Rischio relativo di approvvigionamento
- 5
- Distribuzione delle riserve
- 61
- Stabilità politica (principale produttore)
- 81
- Stabilità politica (principale detentore di riserve)
- 81
Transizioni di fase e allotropi
| Punto di fusione | 336,65 K |
| Punto di ebollizione | 1032,15 K |
| Punto critico (temperatura) | 2223,15 K |
| Punto critico (pressione) | 16 MPa |
Categorie degli stati di ossidazione
Dati di riferimento avanzati
Costanti di schermaggio (6)
| n | Orbitale | σ |
|---|---|---|
| 1 | s | 0,5105 |
| 2 | p | 3,9728 |
| 2 | s | 5,9938 |
| 3 | p | 11,2744 |
| 3 | s | 10,3201 |
| 4 | s | 15,5048 |
Dettaglio dei raggi cristallini (7)
| Carica | CN | Spin | rcrystal (pm) | Origine |
|---|---|---|---|---|
| 1 | IV | 151 | ||
| 1 | VI | 152 | ||
| 1 | VII | 160 | ||
| 1 | VIII | 165 | ||
| 1 | IX | 169 | ||
| 1 | X | 173 | ||
| 1 | XII | 178 |
Modalità di decadimento degli isotopi (53)
| Isotopo | Modalità | Intensità |
|---|---|---|
| 31 | 3p | 100% |
| 32 | p | — |
| 33 | p | — |
| 34 | p | — |
| 35 | B+ | 100% |
| 35 | B+p | 0,4% |
| 36 | B+ | 100% |
| 36 | B+p | 0% |
| 36 | B+A | 0% |
| 37 | B+ | 100% |
Fattori di diffusione dei raggi X (503)
| Energia (eV) | f₁ | f₂ |
|---|---|---|
| 10 | — | 0,03426 |
| 10,1617 | — | 0,03529 |
| 10,3261 | — | 0,03635 |
| 10,4931 | — | 0,03744 |
| 10,6628 | — | 0,03856 |
| 10,8353 | — | 0,03972 |
| 11,0106 | — | 0,04091 |
| 11,1886 | — | 0,04214 |
| 11,3696 | — | 0,0434 |
| 11,5535 | — | 0,04471 |
Dati aggiuntivi
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
2.09×104 milligrams per kilogram
Riferimenti (1)
- [5] Potassium https://education.jlab.org/itselemental/ele019.html
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
3.99×102 milligrams per liter
Riferimenti (1)
- [5] Potassium https://education.jlab.org/itselemental/ele019.html
Sources
Sources of this element.
The metal is the seventh most abundant and makes up about 2.4% by weight of the earth's crust. Most potassium minerals are insoluble and the metal is obtained from them only with great difficulty.
Certain minerals, however, such as sylvite, carnallite, langbeinite, and polyhalite are found in ancient lake and sea beds and form rather extensive deposits from which potassium and its salts can readily be obtained. Potash is mined in Germany, New Mexico, California, Utah, and elsewhere. Large deposits of potash, found at a depth of some 3000 ft in Saskatchewan, promise to be important in coming years.
Potassium is also found in the ocean, but is present only in relatively small amounts, compared to sodium.
Riferimenti (1)
- [6] Potassium https://periodic.lanl.gov/19.shtml
Production
Production of this element (from raw materials or other compounds containing the element).
Potassium is never found free in nature, but is obtained by electrolysis of the hydroxide, much in the same manner as prepared by Davy's first process. Thermal methods also are commonly used to produce potassium (such as by reduction of potassium compounds with CaC2, C, Si, or Na).
Riferimenti (1)
- [6] Potassium https://periodic.lanl.gov/19.shtml
Riferimenti
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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 Potassium.
The element property data was retrieved from publications.