Caesium hydroxide

Caesium hydroxide
Names
	Other names Cesium hydrate
Identifiers
CAS Number	21351-79-1 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:33988 ;
ChemSpider	56494 ;
ECHA InfoCard	100.040.298
EC Number	244-344-1;
PubChem CID	62750;
RTECS number	FK9800000;
UNII	458ZFZ6235;
UN number	2682
CompTox Dashboard (EPA)	DTXSID7066699 ;
	InChI InChI=1S/Cs.H2O/h;1H2/q+1;/p-1 Key: HUCVOHYBFXVBRW-UHFFFAOYSA-M ; InChI=1/Cs.H2O/h;1H2/q+1;/p-1 Key: HUCVOHYBFXVBRW-REWHXWOFAG;
	SMILES [OH-].[Cs+];
Properties
Chemical formula	CsOH
Molar mass	149.912 g/mol
Appearance	Whitish-yellow deliquescent crystals
Density	3.675 g/cm3
Melting point	272 °C (522 °F; 545 K)
Solubility in water	300 g/100 mL at 30 °C
Solubility	Soluble in ethanol
Acidity (pKa)	15.76
Thermochemistry
Heat capacity (C)	69.9 J·mol−1·K−1
Std molar; entropy (S⦵298)	104.2 J·K−1·mol−1
Std enthalpy of; formation (ΔfH⦵298)	−416.2 kJ·mol−1
Hazards
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H302, H314, H361, H373
Precautionary statements	P201, P202, P260, P264, P270, P280, P281, P301+P312, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P308+P313, P310, P314, P321, P330, P363, P405, P501
NFPA 704 (fire diamond)	3 0 1 ALK
Flash point	Not flammable
	Lethal dose or concentration (LD, LC):
LD50 (median dose)	570 mg/kg (oral, rat)
	NIOSH (US health exposure limits):
PEL (Permissible)	none
REL (Recommended)	TWA 2 mg/m3
IDLH (Immediate danger)	N.D.
Safety data sheet (SDS)	ICSC 1592
Related compounds
Other anions	Cæsium oxide; Cæsium fluoride
Other cations	Lithium hydroxide; Sodium hydroxide; Potassium hydroxide; Rubidium hydroxide
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

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. It is the strongest of the five alkali metal hydroxides.^[7] Fused Caesium hydroxide dissolves glass by attacking silica framework and it has applications in bringing glass samples into a solution for analytical purposes in commercial glass industry and defense waste processing facility. The melting process is carried out in a nickel or zirconium crucible.^[8] Caesium hydroxide fusion at 750°C produces complete dissolution of glass pellets.^[8]

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

It is an anisotropic etchant of silicon, exposing octahedral 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 potassium hydroxide.

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 and potassium hydroxide, although more reactive.

References

^ Lide, David R. (1998), Handbook of Chemistry and Physics (87 ed.), Boca Raton, Florida: CRC Press, pp. 4–51, ISBN 0-8493-0594-2
^ "Sortierte Liste: pKb-Werte, nach Ordnungszahl sortiert. – Das Periodensystem online".
^ "ICSC 1592 - Cesium Hydroxide".
^ Lide, David R. (1998), Handbook of Chemistry and Physics (87 ed.), Boca Raton, Florida: CRC Press, pp. 5–14, ISBN 0-8493-0594-2
^ ^a ^b ^c NIOSH Pocket Guide to Chemical Hazards. "#0111". National Institute for Occupational Safety and Health (NIOSH).
^ Gigiena Truda i Professional'nye Zabolevaniya. Labor Hygiene and Occupational Diseases., 21(1)(29), 1977
^ Considine, Douglas M.; Considine, Glenn D. (2013-12-11). Van Nostrand's Scientific Encyclopedia. Springer Science & Business Media. ISBN 978-1-4757-6918-0.
^ ^a ^b Coleman, C.J; Spencer, W.A. (April 1998). "CsOH is a very strong base that attacks the silica framework of glass under fusion conditions. Cesium Hydroxide Fusion Dissolution of Analytical Reference Glass-1 in Both Powder and Shard Form" (PDF). Westinghouse Savannah River Company. CsOH is a very strong base that attacks the silica framework of glass under fusion conditions.

External links

[hand-1] Lide, David R. (1998), Handbook of Chemistry and Physics (87 ed.), Boca Raton, Florida: CRC Press, pp. 4–51, ISBN 0-8493-0594-2

[2] "Sortierte Liste: pKb-Werte, nach Ordnungszahl sortiert. – Das Periodensystem online".

[3] "ICSC 1592 - Cesium Hydroxide".

[hand2-4] Lide, David R. (1998), Handbook of Chemistry and Physics (87 ed.), Boca Raton, Florida: CRC Press, pp. 5–14, ISBN 0-8493-0594-2

[PGCH-5] NIOSH Pocket Guide to Chemical Hazards. "#0111". National Institute for Occupational Safety and Health (NIOSH).

[6] Gigiena Truda i Professional'nye Zabolevaniya. Labor Hygiene and Occupational Diseases., 21(1)(29), 1977

[7] Considine, Douglas M.; Considine, Glenn D. (2013-12-11). Van Nostrand's Scientific Encyclopedia. Springer Science & Business Media. ISBN 978-1-4757-6918-0.

[:0-8] Coleman, C.J; Spencer, W.A. (April 1998). "CsOH is a very strong base that attacks the silica framework of glass under fusion conditions. Cesium Hydroxide Fusion Dissolution of Analytical Reference Glass-1 in Both Powder and Shard Form" (PDF). Westinghouse Savannah River Company. CsOH is a very strong base that attacks the silica framework of glass under fusion conditions.

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