Editing Potassium (section)

==Occurrence==
[[File:PotassiumFeldsparUSGOV.jpg|thumb|left|upright|Potassium in [[feldspar]]]]

Potassium is formed in [[supernova]]e by [[nucleosynthesis]] from lighter atoms. Potassium is principally created in Type II supernovae via an [[Supernova nucleosynthesis|explosive oxygen-burning process]].<ref>{{cite journal|first1= V.|last1= Shimansky|title=Observational constraints on potassium synthesis during the formation of stars of the Galactic disk| journal=Astronomy Reports|date=September 2003|bibcode = 2003ARep...47..750S|last2= Bikmaev|first2=I. F.|last3= Galeev|first3=A. I.|last4= Shimanskaya|first4=N. N.|last5= Ivanova|first5=D. V.|last6= Sakhibullin|first6=N. A.|last7= Musaev|first7=F. A.|last8= Galazutdinov|first8=G. A.|volume= 47|pages= 750–762|doi= 10.1134/1.1611216|issue= 9|s2cid= 120396773}}</ref> These are nuclear [[Nuclear_Fusion|fusion]] reactions, not to be confused with chemical burning of potassium in oxygen. {{chem|40|K}} is also formed in {{Nowrap|[[s-process]]}} nucleosynthesis and the [[neon burning process]].<ref>{{cite journal|last1=The|first1=L.-S.|last2=Eid|first2=M. F. El|last3=Meyer|first3=B. S.|date=2000|title=A New Study of s-Process Nucleosynthesis in Massive Stars|journal=The Astrophysical Journal|volume=533|issue=2|pages=998|doi=10.1086/308677|issn=0004-637X|arxiv=astro-ph/9812238|bibcode=2000ApJ...533..998T|s2cid=7698683}}</ref>

Potassium is the 20th most abundant element in the [[Solar System]] and the 17th most abundant element by weight in the Earth. It makes up about 2.6% of the weight of the [[Earth's crust]] and is the seventh most abundant element in the crust.<ref>[[#Greenwood|Greenwood]], p. 69</ref> The potassium concentration in seawater is 0.39{{nbsp}}g/L<ref name="seawaterconcentration" /> (0.039 wt/v%), about one twenty-seventh the concentration of sodium.<ref name="geo">{{cite book|url = https://books.google.com/books?id=NXEmcGHScV8C&pg=PA3| publisher = Springer| date = 2009|title = Seawater Desalination: Conventional and Renewable Energy Processes|first1= Giorgio |last1=Micale| first2=Andrea |last2=Cipollina| first3=Lucio |last3=Rizzuti|page = 3| isbn = 978-3-642-01149-8}}</ref><ref name="indus">{{cite book|chapter-url = https://books.google.com/books?id=zNicdkuulE4C&pg=PA723| title =Industrial minerals & rocks: commodities, markets, and uses|publisher = Society for Mining, Metallurgy, and Exploration|date= 2006| first1= Michel|last1=Prud'homme|first2= Stanley T.| last2 = Krukowski|chapter = Potash|pages = 723–740|isbn = 978-0-87335-233-8}}</ref>

===Geology===
Elemental potassium does not occur in nature because of its high reactivity. It reacts violently with water<ref name="HollemanAF" /> and also reacts with oxygen. [[Orthoclase]] (potassium feldspar) is a common rock-forming mineral. [[Granite]] for example contains 5% potassium, which is well above the average in the Earth's crust. [[Sylvite]] (KCl), [[carnallite]] ({{chem2|KCl*MgCl2*6H2O}}), [[kainite]] ({{chem2|MgSO4*KCl*3H2O}}) and [[langbeinite]] ({{chem2|MgSO4*K2SO4}}) are the minerals found in large [[evaporite]] deposits worldwide. The deposits often show layers starting with the least soluble at the bottom and the most soluble on top.<ref name="indus" /> Deposits of niter ([[potassium nitrate]]) are formed by decomposition of organic material in contact with atmosphere, mostly in caves; because of the good water solubility of niter the formation of larger deposits requires special environmental conditions.<ref>{{cite book|chapter-url = https://books.google.com/books?id=NyUDAAAAMBAJ&pg=PA134|pages = 134–145| chapter = The Origin of Nitrate Deposits| first = William H.| last = Ross|title = Popular Science|date = 1914|publisher=Bonnier Corporation}}</ref>