Potassium (K) Elemental Symbol

French German Italian Portuguese Spanish Swedish
Potassium Kalium Potassio Potássio Potasio Kalium

Potassium(K) atomic and molecular weight, atomic number and elemental symbolPotassium is a Block S, Group 1, Period 4 element. The number of electrons in each of Potassium's shells is 2, 8, 8, 1 and its electron configuration is [Ar] 4s1. The potassium atom has a radius of 227.2 pm and its Van der Waals radius is 275 pm. In its elemental form, CAS 7440-09-7, potassium has a silvery gray appearance. Potassium is the seventh most abundant element on earth. Elemental Potassium It is one of the most reactive and electropositive of all metals and rapidly oxidizes. Potassium Bohr Model As with other metals of the alkali group, the metal decomposes in water with the evolution of hydrogen. Since potassium reacts violently with water, it only occurs in nature in ionic salts. Potassium was first discovered by Sir Humphrey Davy in 1807. The origin of the element name comes from the English word 'potash' meaning pot ashes and the Arabic word 'qali' which means alkali. The symbol K originates from the Latin word 'kalium'. Potassium information, including technical data, safety data, high purity properties, research, applications and other useful facts are discussed below. Scientific facts such as the atomic structure, ionization energy, abundance on earth, conductivity and thermal properties are also included.

High purity potassium compounds have numerous pharmacological, medical, and electronics applications. High Purity (99.999%) Potassium Oxide (K2O) PowderImportant compounds include the hydroxide, nitrate, carbonate, chloride, bromide, iodide, and sulfate. Lower purity compounds are used in pyrotechnics for its violet color on ignition and in glass and ceramic glazes to produce this color. Potassium is also used as a nutrient in plant growth. Potassium is available as metal and compounds with purities from 99% to 99.999% (ACS grade to ultra-high purity). Elemental or metallic forms include pellets, rod, wire and granules for evaporation source material purposes. High Purity (99.999%) Potassium (K) Sputtering TargetNanoparticles and nanopowders provide ultra-high surface area which nanotechnology research and recent experiments demonstrate function to create new and unique properties and benefits. Oxides are available in powder and dense pellet form for such uses as optical coating and thin film applications. Oxides tend to be insoluble. Fluorides are another insoluble form for uses in which oxygen is undesirable such as metallurgy, chemical and physical vapor deposition and in some optical coatings. Potassium is available in soluble forms including chlorides, nitrates and acetates. These compounds are also manufactured as solutions at specified stoichiometries.

Potassium is not toxic in its elemental form; however, safety data for its compounds can vary widely depending on the form. For potential hazard information, toxicity, and road, sea and air transportation limitations, such as DOT Hazard Class, DOT Number, EU Number, NFPA Health rating and RTECS Class, please see the specific material or compound referenced in the Products tab below.

  • Properties
  • Safety Data
  • Products
  • Research
  • Isotopes
  • Other Elements

Potassium Properties

Symbol: K Melting Point: 63.5 oC, 146.3 oF, 336.65 K
Atomic Number: 19 Boiling Point: 759 oC, 1398.2 oF, 1032.15 K
Atomic Weight: 39.0983 Density: 0.862 g·cm−3
Element Category: alkali metal Liquid Density @ Melting Point: 0.828 g·cm−3
Group, Period, Block: 1, 4, s Specific Heat: 0.753 @20°C J/g mol
    Heat of Vaporization 79.1 kJ mol-1
CHEMICAL STRUCTURE Heat of Fusion 2.4 kJ mol-1
Electrons: 19 Thermal Conductivity: 102.5 W·m−1·K−1
Protons: 19 Thermal Expansion: (25 °C) 83.3 µm·m−1·K−1
Neutrons: 20 Electrical Resistivity: (20 °C) 72 nΩ·m
Electron Configuration: [Ar] 4s1 Electronegativity: 0.82 (Pauling scale)
Atomic Radius: 227 pm Tensile Strength: N/A
Covalent Radius: 203 ±12 pm Molar Heat Capacity: 29.6 J·mol−1·K−1
Van der Waals radius: 275 pm Young's Modulus: 3.53 GPa
Oxidation States: 1 (strongly basic oxide) Shear Modulus: 1.3 GPa
Phase: Solid Bulk Modulus: 3.1 GPa
Crystal Structure: body-centered cubic Poisson Ratio: N/A
Magnetic Ordering: paramagnetic Mohs Hardness: 0.4
1st Ionization Energy: 418.81 kJ mol-1 Vickers Hardness: N/A
2nd Ionization Energy: 3051.85 kJ mol-1 Brinell Hardness: 0.363 MPa
3rd Ionization Energy: 4419.64 kJ mol-1 Speed of Sound: (20 °C) 2000 m·s−1
CAS Number: 7440-09-7  Abundance in typical human body, by weight: 2000000 ppb
ChemSpider ID: 4575326 Abundance in typical human body, by atom: 320000 ppb
PubChem CID: 5462222 Abundance in universe, by weight: 3000 ppb
MDL Number: MFCD00133776 Abundance in universe, by atom: 100 ppb
EC Number: N/A Discovered By: Humphry Davy
Beilstein Number: N/A Discovery Date: 1807
SMILES Identifier: [K]  
InChI Identifier: InChI=1S/K Other Names: Kalium, Potássio, Draslík, Kalij

Potassium Products

Metal Forms  •  Compounds  •  Oxide Forms  •  Organometallic Compounds
Sputtering Targets  •  Nanomaterials  •  Semiconductor Materials •  Isotopes

Metal Forms

Potassium Balls
Potassium Bands
Potassium Board
Potassium Briquette
Potassium Capsules
Potassium Chunk
Potassium Circle
Potassium Coil
Potassium Coins
Potassium Cubes
Potassium Cylinder
Potassium Disc
Potassium Flanges
Potassium Foil
Potassium Fragments
Potassium Metal
Potassium Nugget
Potassium Parts
Potassium Pebbles
Potassium Pellets
Potassium Pills
Potassium Rings
Potassium Rocks
Potassium Sleeves
Potassium Spring
Potassium Strip
Potassium Tape
Potassium Wafer
Potassium Wire

Organometallic Compounds

Antimony Potassium Tartrate
Antimony Potassium Tartrate Hydrate
Antimony Potassium Tartrate Trihydrate
Bismuth Potassium Citrate
Cobalt Potassium Citrate
Dipotassium Dihydrogen Ethylenediaminetetraacetic Acid Dihydrate
Dipotassium Phthalate
Potassium 2,2'-bithiophene-5-trifluoroborate
Potassium 2-chlorophenyltrifluoroborate
Potassium 2-Ethylhexanoate
Potassium 2,4-Difluorophenyltrifluoroborate
Potassium Acetylacetonate Hemihydrate
Potassium Antimony Tartrate
Potassium Benzoate
Potassium beta-hydroxypyruvate
Potassium bis(oxalato)Cuprate(II) Hydrate
Potassium bis(oxalato)Platinate(II) Dihydrate
Potassium Bitartrate
Potassium Chromium(III) Oxalate Trihydrate
Potassium Citrate
Potassium Citrate Dibasic
Potassium Citrate Monohydrate
Potassium Cyclohexanebutyrate
Potassium Ethoxide
Potassium Formate
Potassium Heptadecafluoro-1-Octanesulfonate
Potassium L-Lactate Solution
Potassium Nitridotrioxoosmate(VIII)
Potassium Oxalate Anhydrous
Potassium Oxalate Monohydrate
Potassium p-toluenethiosulfonate
Potassium Sodium L-tartrate Tetrahydrate
Potassium Sodium Tartrate Solution
Potassium Stannate Trihydrate
Potassium Tartrate Hemihydrate
Potassium tetrakis(2-thienyl)borate
Potassium Tetrakis(4-biphenylyl)borate
Potassium Tetrakis[3,5-bis(trifluoromethyl)phenyl]borate
Potassium Tetraoxalate
Potassium Thioacetate
Potassium Titanium Oxide Oxalate Dihydrate
Potassium Trifluoromethanesulfonate
Potassium Trioxalatochromate
Potassium Trioxalatocobaltate
Potassium Trioxalatoferrate(III) Trihydrate
Tetrabromophenolphthalein Ethyl Ester Potassium Salt

Potassium Targets

Potassium Oxide Sputtering Target
Potassium Sputtering Target


Potassium 40 Chloride Isotope
Potassium 41 Chloride Isotope


Potassium Sodium
Potassium Sodium Ampoule Alloy


Aluminum Potassium Sulfate
Chromium Potassium Sulfate
Chromium Potassium Sulfate Dodecahydrate
Chromium Potassium Sulfate Solution
Dipotassium Hexachloroiridate
Gold(I) Potassium Cyanide
Gold(III) Potassium Thiocyanate
Iridium Potassium Cyanide
Lead Potassium Niobium Oxide
Lithium Potassium Acetyl Phosphate
Lithium Potassium Chloride
Mercuric Potassium Iodide
Muscovite Mica Sheet
Palladium(II) Potassium Thiosulfate Monohydrate
Potassium (3-chlorophenyl)trifluoroborate
Potassium 4-chlorophenyltrifluoroborate
Potassium Acetate
Potassium Acetate Solution
Potassium Aquapentachlororuthenate(III) Dimer
Potassium Arsenate Monobasic
Potassium Arsenate
Potassium Bicarbonate
Potassium Bifluoride
Potassium Biiodate
Potassium Biiodate Solution
Potassium bis(fluorosulfonyl)imide
Potassium bis(trifluoromethanesulfonyl)imide
Potassium Bisulfate
Potassium Borohydride
Potassium Briquette
Potassium Bromate
Potassium Bromide
Potassium Bromide, Ultra Dry
Potassium Carbide
Potassium Carbonate
Potassium Carbonate, Anhydrous
Potassium Carbonate Sesquihydrate
Potassium Chlorate
Potassium Chloride
Potassium Chloride, Ultra Dry
Potassium Chloride/Silver Chloride Solution
Potassium Chloride Solution
Potassium Chlorochromate
Potassium Chloroplatinate
Potassium Chloropalladate
Potassium Chloropalladite
Potassium Chromate
Potassium copper(I) cyanide
Potassium Cyanide
Potassium Cyanate
Potassium Dichromate
Potassium Disulfate
Potassium Dicyanoargentate
Potassium Dihydrogen Phosphate
Potassium Dideuterium Phosphate
Potassium Dinitrosulfatopalladate(II), Solution
Potassium Disulfitopalladate(II)
Potassium Ferrate
Potassium Ferricyanide
Potassium Ferrocyanide Solution
Potassium Fluoride
Potassium Fluoride Dihydrate
Potassium Fluoride on Aluminum Oxide
Potassium Fluorosulfate
Potassium Gold(III) Chloride
Potassium Graphite
Potassium Heptafluoroniobate
Potassium Heptafluorotantalate
Potassium Hexabromoiridate(IV)
Potassium Hexabromoosmiate
Potassium Hexabromoplatinate
Potassium Hexabromorhenate
Potassium Hexabromotellurate(IV)
Potassium Hexachloroiridate(III)
Potassium Hexachloroiridate(III) Hydrate
Potassium Hexachloroosmiate(IV)
Potassium Hexachloropalladate(IV)
Potassium Hexachloroplatinate
Potassium Hexachloroplatinate(IV)
Potassium Hexachlororhenate
Potassium Hexachlorotellurate
Potassium Hexachlororuthenate(IV)
Potassium Hexacyanochromate(III)
Potassium Hexacyanocobaltate(III)
Potassium Hexacyanoferrate(II) Trihydrate
Potassium Hexacyanoiridate (III) Hydrate
Potassium Hexacyanomanganate
Potassium Hexacyanoplatinate(IV)
Potassium Hexacyanoruthenate(II) Hydrate
Potassium Hexafluoroaluminate
Potassium Hexafluoroantimonate(V)
Potassium Hexafluoroarsenate(V)
Potassium Hexafluorogermanate
Potassium Hexafluoronickelate(IV)
Potassium Hexafluorophosphate
Potassium Hexafluorotitanate(IV)
Potassium Hexafluorozirconate
Potassium Hydride
Potassium Hydrogen Carbonate
Potassium Hydrogen Fluoride
Potassium Hydrogen Iodate
Potassium Hydrogen Phosphate
Potassium Hydrogen Phthalate
Potassium Hydrogen Sulfate
Compounds (continued)

Potassium Hydroxide
Potassium Hydroxide Flake
Potassium Hydroxide Pellets
Potassium Hydroxide Prisms
Potassium Imidodisulfonate
Potassium Iodate
Potassium Iodide
Potassium Iodide, Ultra Dry
Potassium Manganate
Potassium Metabisulfite
Potassium Metal
Potassium Metavanadate
Potassium Molybdate
Potassium Nickel(IV) Paraperiodate
Potassium Niobium Oxide
Potassium Nitrate
Potassium Nitrate Solution
Potassium Osmium(VI) Oxide Dihydrate
Potassium Oxide
Potassium p-toluenethiosulfonate
Potassium Pentachloronitrosylruthenate(II)
Potassium Pentachlororhodate(III)
Potassium Pentachlororhodate(III) Hydrate
Potassium Pentachlororuthenate(III) Hydrate
Potassium Perchlorate
Potassium Periodate
Potassium Permanganate
Potassium Peroxydisulfate
Potassium Perrhenate
Potassium Persulfate
Potassium Phosphate
Potassium Ruthenate
Potassium Selenate
Potassium Selenite
Potassium Silicofluoride
Potassium Sulfate
Potassium Sulfate Solution
Potassium Sulfide
Potassium Tantalum Niobium Oxide
Potassium Tantalum Oxide
Potassium Tellurate
Potassium Tellurite
Potassium Tetraborate Tetrahydrate
Potassium Tetrabromoaurate(III) Dihydrate
Potassium Tetrabromopalladate(II)
Potassium Tetrabromoplatinate
Potassium Tetrachloroaurate(III) Hydrate
Potassium Tetrachloropalladate(II)
Potassium Tetrachloroplatinate(II)
Potassium Tetracyanonickelate(II)
Potassium Tetracyanonickelate(II) Hydrate
Potassium Tetracyanopalladate(II) Hydrate
Potassium Tetracyanoplatinate(II) Hydrate
Potassium Tetracyanoplatinate(II) Trihydrate
Potassium Tetrafluoroaluminate
Potassium Tetrafluoroborate
Potassium Tetranitropalladate(II)
Potassium Tetranitroplatinate(II)
Potassium Tetraphenylborate
Potassium Tetraphenylborate
Potassium Thiocyanate
Potassium Thiosulfate Sesquihydrate
Potassium Titanate Anhydrous
Potassium Titanyl Oxalate
Potassium Titanyl Phosphate
Potassium Titanyl Arsenate
Potassium Trichloro(ethylene)platinate(II) Hydrate
Potassium Trichloroammineplatinate(II)
Potassium Trchloro(ethylene)platinate(II) Hydrate
Potassium Trichloroammineplatinate(II)
Potassium Triethylborohydride Solution
Potassium Tungstate
Silver Potassium Cyanide
Silver Potassium Iodide

Crystal/Semiconductor Materials

KBBF Crystal, Nonlinear
Neodymium doped Potassium-Gadolinium Tungstate
Potassium Niobate/Barium Nickel Niobate
Potassium Phosphide
Ytterbium doped Potassium-Gadolinium Tungstate
Ytterbium doped Potassium Yttrium Tungstate

Potassium Oxide Forms

Potassium Oxide Nanopowder
Potassium Oxide Pellets
Potassium Oxide Piecess
Potassium Oxide Powder
Potassium Oxide Shot
Potassium Oxide Sputtering Target
Potassium Oxide Tablets


Potassium Hydroxide Nanoprisms
Potassium Oxide Nanopowder

Recent Research & Development for Potassium

  • Comparison of 10% potassium hydroxide solution versus cryotherapy in the treatment of molluscum contagiosum: An open randomized clinical trial. Handjani F, Behazin E, Sadati MS. J Dermatolog Treat. 2014.
  • Treatment of pediatric molluscum contagiosum with 10% potassium hydroxide solution. Can B, Topaloglu F, Kavala M, Turkoglu Z, Zindanci I, Sudogan S. J Dermatolog Treat. 2014 Jun.
  • Relationships between the leaf and fruit mineral compositions of Actinidia deliciosa var. Hayward according to nitrogen and potassium fertilization. Santoni F, Paolini J, Barboni T, Costa J. Food Chem. 2014 Mar.
  • Combined effects of potassium lactate and calcium ascorbate as sodium chloride substitutes on the physicochemical and sensory characteristics of low-sodium frankfurter sausage. Choi YM, Jung KC, Jo HM, Nam KW, Choe JH, Rhee MS, Kim BC. Meat Sci. 2014 Jan.
  • Growth, structure and spectral studies of a novel mixed crystal potassium zinc manganese sulphate. Vijila Manonmoni J, Bhagavannarayana G, Ramasamy G, Meenakshisundaram S, Amutha M. Spectrochim Acta A Mol Biomol Spectrosc. 2014 Jan.
  • The effect of counter-ions on the ion selectivity of potassium and sodium ions in nanopores. Tang D, Kim D. Biomed Mater Eng. 2014
  • Calcium and potassium content in beef: Influences on tenderness and associations with molecular markers in Nellore cattle. Tizioto PC, Gromboni CF, de Araujo Nogueira AR, de Souza MM, de Alvarenga Mudadu M, Tholon P, Rosa Ado N, Tullio RR, Medeiros SR, Nassu RT, de Almeida Regitano LC. Meat Sci. 2014 Jan.
  • A Systematic Review of the Uterine Relaxant Effect of Potassium Channel Openers. Hantooshzadeh S, Rezaeizadeh G, Nikfar S, Ghiasi S, Abdollahi M. Curr Drug Discov Technol. 2013 Dec
  • Effect of raw material ratios on the compressive strength of magnesium potassium phosphate chemically bonded ceramics. Wang AJ, Yuan ZL, Zhang J, Liu LT, Li JM, Liu Z. Mater Sci Eng C Mater Biol Appl. 2013 Dec 1.
  • Combined effects of potassium sorbate, hot water and thiabendazole against green mould of citrus fruit and residue levels. D'Aquino S, Fadda A, Barberis A, Palma A, Angioni A, Schirra M. Food Chem. 2013 Nov 15.
  • Aptamer biosensor for label-free impedance spectroscopy detection of potassium ion based on DNA G-quadruplex conformation. Chen Z, Chen L, Ma H, Zhou T, Li X. Biosens Bioelectron. 2013.
  • Protective effects of hydrogen sulfide in a rat model of traumatic brain injury via activation of mitochondrial adenosine triphosphate-sensitive potassium channels and reduction of oxidative stress. Jiang X, Huang Y, Lin W, Gao D, Fei Z. J Surg Res. 2013 Oct
  • Influence of metakaolin purities on potassium geopolymer formulation: The existence of several networks. Autef A, Joussein E, Poulesquen A, Gasgnier G, Pronier S, Sobrados I, Sanz J, Rossignol S. J Colloid Interface Sci. 2013.
  • Gain control of synaptic response function in cerebellar nuclear neurons by a calcium-activated potassium conductance. Feng SS, Lin R, Gauck V, Jaeger D. Cerebellum. 2013.
  • A computational study of barium blockades in the KcsA potassium channel based on multi-ion potential of mean force calculations and free energy perturbation. Rowley CN, Roux B. J Gen Physiol. 2013.
  • Formulation and evaluation of non-effervescent floating tablets of losartan potassium. Getyala A, Gangadharappa HV, Prasad MS, Reddy MP, Kumar TM. Curr Drug Deliv. 2013 Oct.
  • SDF-1a and LPA modulate microglia potassium channels through rho gtpases to regulate cell morphology. Muessel MJ, Harry GJ, Armstrong DL, Storey NM. Glia.
  • Paradoxical Activation of an Inwardly Rectifying Potassium Channel Mutant by Spermine: "(B)locking" Open the Bundle Crossing Gate. Vilin YY, Nunez JJ, Kim RY, Dake GR, Kurata HT. Mol Pharmacol. 2013.
  • Potassium Channel Openers Increase Aortic Elastic Fiber Formation and Reverse the Genetically Determined Elastin Deficit in the BN Rat. Slove S, Lannoy M, Behmoaras J, Pezet M, Sloboda N, Lacolley P, Escoubet B, Buján J, Jacob MP. Hypertension. 2013 Oct.
  • Property changes of urinary nanocrystallites and urine of uric acid stone formers after taking potassium citrate. Zhang GN, Ouyang JM, Xue JF, Shang YF. Mater Sci Eng C Mater Biol Appl. 2013 Oct.
  • Subcellular potassium and sodium distribution in Saccharomyces cerevisiae wild-type and vacuolar mutants. Herrera R, Alvarez MC, Gelis S, Ramos J. Biochem J. 2013.

Potassium Isotopes

Potassium (K) has 25 isotopes ranging from 32K to 56K. Three of these occur naturally: 39K (93.3%), 41K (6.7%), and 40K (0.012%).

Nuclide Symbol Isotopic Mass Half-Life Nuclear Spin
39K 38.96370668 Stable 3/2+
40K 39.96399848 1.248(3)×109 a 4-
41K 40.96182576 Stable 3/2+