Caesium hydroxide is a strong base (pK_a= 15.76) containing the highly reactive alkali metal caesium, much like the other alkali metal hydroxides such as sodium hydroxide and

potassium hydroxide Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which exp ...

. Caesium hydroxide is corrosive enough to quickly dissolve through glass. Due to its high reactivity, caesium hydroxide is extremely

hygroscopic Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption or adsorption from the surrounding environment, which is usually at normal or room temperature. If water molecules become suspended among the substan ...

. Laboratory caesium hydroxide is typically a hydrate. It is an anisotropic etchant of

silicon Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic luster, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic ta ...

, exposing

octahedral In geometry, an octahedron (plural: octahedra, octahedrons) is a polyhedron with eight faces. The term is most commonly used to refer to the regular octahedron, a Platonic solid composed of eight equilateral triangles, four of which meet a ...

planes. This technique can form pyramids and regularly shaped etch pits for uses such as Microelectromechanical systems. It is known to have a higher selectivity to etch highly p-doped silicon than the more commonly used

. This compound is not commonly used in experiments due to the high extraction cost of caesium and its reactive behaviour. It acts in similar fashion to the compounds

rubidium hydroxide Rubidium hydroxide is the inorganic compound with the formula RbOH. It consists of rubidium cations and an equal number of hydroxide anions. It is a colorless solid that is commercially available as aqueous solutions from a few suppliers. Like ot ...

and

, although more reactive.

References

External links

NIOSH Pocket Guide to Chemical Hazards

NIST Standard Reference Database
{{Authority control Caesium compounds Hydroxides Deliquescent substances