View source for Caesium hydroxide

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{{chembox
|   Name = Caesium hydroxide
| Section1 = {{Chembox Identifiers
|   InChI = 1/Cs.H2O/h;1H2/q+1;/p-1
|   StdInChI = 1S/Cs.H2O/h;1H2/q+1;/p-1
|   InChIKey = HUCVOHYBFXVBRW-REWHXWOFAG
|   StdInChIKey = HUCVOHYBFXVBRW-UHFFFAOYSA-M
|   CASNo = 21351-79-1
|    CASNo_Ref = {{cascite}}
|   EC-number = 244-344-1
|   ChemSpiderID = 56494
|   RTECS = FK9800000
|   UNNumber = 2682
  }}
| Section2 = {{Chembox Properties
|   Reference = <ref>{{RubberBible62nd|page=B-92}}.</ref>
|   Formula = CsOH
|   MolarMass = 149.91 g/mol
|   Appearance = whitish-yellow solid, deliquescent
|   Density = 3.675 g/cm<sup>3</sup>, solid
|   MeltingPt = 273.3 °C
|   Solubility = 395.5 g/100 ml at 15 °C
|   Solubility1 = soluble
|    Solvent1 = ethanol
  }}
| Section4 = {{Chembox Thermochemistry
|   Reference = <ref>{{RubberBible87th|page=5-14}}.</ref>
|   DeltaHf = −416.2 kJ/mol
|   Entropy = 104.2 J&thinsp;K<sup>−1</sup>&thinsp;mol<sup>−1</sup>
|   HeatCapacity = 69.9 J&thinsp;K<sup>−1</sup>&thinsp;mol<sup>−1</sup>
  }}
| Section7 = {{Chembox Hazards
|   ExternalMSDS = {{ICSC-small|15|92}}
|   EUIndex = not listed
|   FlashPt = non-flammable
  }}
| Section8 = {{Chembox Related
|   OtherAnions = [[Caesium oxide]]
|   OtherCations = [[Lithium hydroxide]]<br/>[[Sodium hydroxide]]<br/>[[Potassium hydroxide]]<br/>[[Rubidium hydroxide]]
  }}
}}
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{{chembox
| Name = Caesium hydroxide monohydrate
| Section1 = {{Chembox Identifiers
|   InChI = 1/Cs.2H2O/h;2*1H2/q+1;;/p-1
|   StdInChI = 1S/Cs.2H2O/h;2*1H2/q+1;;/p-1
|   InChIKey = ABSOMGPQFXJESQ-REWHXWOFAC
|   StdInChIKey = ABSOMGPQFXJESQ-UHFFFAOYSA-M
|   CASNo = 35103-79-8 <!-- from Chemetall -->
|   EC-number = 244-344-1
|   ChemSpiderID = 10620883
  }}
| Section2 = {{Chembox Properties
|   Formula = CsOH·H<sub>2</sub>O
|   MolarMass = 167.93 g/mol
  }}
}}
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'''Caesium hydroxide''' (CsOH) is a [[chemical compound]] consisting of an atom of [[caesium]] and a [[hydroxide]] group (also known as [[hydroxyl]]).  It is a powerful [[base (chemistry)|base]], much like other [[alkali hydroxide|alkali metal hydroxides]] such as [[sodium hydroxide]] and [[potassium hydroxide]].  In fact, caesium hydroxide is powerful enough to quickly corrode through glass.

Due to its high reactivity, caesium hydroxide is extremely [[hygroscopic]].  Laboratory caesium hydoxide is typically a [[hydrate]].

It is an anisotropic etchant of [[silicon]], exposing [[octahedron|octahedral]] planes. This technique can create pyramids and regularly-shaped etch pits for uses such as [[MEMS]]. It is known to have a higher selectivity to etch highly p-doped silicon than the more commonly used [[potassium hydroxide]].{{fact}}

However, this compound is not usually used in experiments as the extraction of caesium is very expensive and the fact that it behaves very much like [[rubidium hydroxide]] and [[potassium hydroxide]] but reacts chemically stronger than they do.

Caesium hydroxide can be obtained by the following chemical reaction:
:2Cs + 2H<sub>2</sub>O → 2CsOH + H<sub>2</sub>
The above reaction occurs explosively with enough force to shatter a [[Pyrex]] beaker.

==References==
{{reflist}}

==Further reading==
*{{OrgSynth | first1 = E. J. | last1 = Corey | authorlink1 = Elias James Corey | first2 = Mark C. | last2 = Noe | title = Preparation of ''O''-Allyl-''N''-(9-anthracenylmethyl)cinchonidinium Bromide as a Phase Transfer Catalyst for the Enantioselective Alkylation of Glycine Benzophenone Imine ''tert''-Butyl Ester: (4''S'')-2-(Benzhydrylidenamino)pentanedioic Acid, 1-''tert''-Butyl Ester-5-Methyl Ester | prep = v80p0038 | volume = 80 | pages = 38 | year = 2003}}.

==External links==
*{{ICSC|15|92}}
*{{PGCH|0111}}

[[Category:Caesium compounds]]
[[Category:Hydroxides]]

{{Imported from Wikipedia|name=Caesium hydroxide|id=307094254}}