NaK 300935 220363071 2008-06-19T14:23:09Z Duckysmokton 2063531 /* References */ iw fr {{for|other meanings|Nak (disambiguation)}} {{Chembox new | ImageFile = | ImageSize = | IUPACName = | OtherNames = | Section1 = {{Chembox Identifiers | CASNo = 11135-81-2 | PubChem = | SMILES = }} | Section2 = {{Chembox Properties | Formula = N/A | MolarMass = N/A | Appearance = Liquid metal | Density = 0.866 g/mL (variable) | MeltingPt = | BoilingPt = | Solubility = }} | Section3 = {{Chembox Hazards | MainHazards = '''Flammable''' ('''F'''), '''Corrosive''' ('''C''') | FlashPt = | Autoignition = }} }} '''NaK''' (often pronounced as such, rhyming with "sack") is an alloy of [[sodium]] (Na) and [[potassium]] (K), and particularly one that is liquid at room temperatures. It is a commercially available material in various grades. NaK is highly reactive with air or water, and must be handled with special precautions. Quantities as small as one gram can be a fire or explosion risk. ==Physical properties== Alloys with between about 40% and 90% potassium by weight are liquid at room temperature. The mixture with the lowest melting point (the [[eutectic]] mix), consisting of 78% potassium and 22% sodium, is liquid from &minus;12.6 to 785 °C, and has a density of 866&nbsp;kg/m³ at 21°C and 855&nbsp;kg/m³ at 100°C.<ref>{{cite web | title=BASF Corporation &ndash; Sodium-Potassium Alloy (NaK) | url=http://www.basf.com/inorganics/pdfs/tech_datasheet/NaK.pdf | accessmonthday=September 13 | accessyear=2006 }}</ref> ==Usage== ===As coolant=== One notable use is as the [[coolant]] in experimental [[Fast neutron reactor|fast neutron nuclear reactor]]s. Unlike commercial plants, these are frequently shut down and defuelled. Use of [[lead]] or pure sodium, the other materials used in practical reactors, would require continual heating to maintain the coolant as a liquid. Use of NaK overcomes this. NaK is used in many other heat transfer applications for similar reasons. The Soviet [[RORSAT]] radar satellites were powered by a NaK-cooled reactor. Apart from the wide liquid temperature range, NaK has a very low [[vapor pressure]], important in the vacuum of [[Outer space|space]]. Some of the coolant has leaked and these NaK droplets constitute a significant [[space debris]] hazard.{{Fact|date=December 2007}} ===In catalysis=== NaK is also used as a catalyst for many reactions, including precursors of [[ibuprofen]]. ===As desiccant=== Both sodium and potassium are used as [[desiccant]]s in drying solvents prior to distillation. However, without heating, the solid metal is only able to react at the surface. Formation of oxide crusts also reduces the reactivity. As a liquid metal alloy at room temperature, the use of NaK as a [[desiccant]] helps to avoid these problems. ==References== <div class="references-small"> <references/> </div> [[Category:Fusible alloys]] [[Category:Coolants]] [[Category:Potassium]] [[Category:Sodium]] [[Category:desiccants]] {{alloy-stub}} [[ca:NaK]] [[fr:NaK]] [[ja:ナトリウムカリウム合金]] [[pt:NaK]] [[vi:NaK]] [[zh:钠钾合金]]