Caesium hydroxide
| Names | |
|---|---|
| Other names
Cesium hydrate | |
| Identifiers | |
21351-79-1  | |
| ChEBI | CHEBI:33988 |
| ChemSpider | 56494 |
| EC Number | 244-344-1 |
| Jmol 3D model | Interactive image |
| RTECS number | FK9800000 |
| UN number | 2682 |
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| Properties | |
| 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)[1] |
| 300 g/100 mL at 30 °C | |
| Solubility | Soluble in ethanol[2] |
| Basicity (pKb) | -1.76[3] |
| Thermochemistry | |
| 69.9 J·mol−1·K−1[4] | |
| Std molar entropy (S |
104.2 J·K−1·mol−1 |
| Std enthalpy of formation (ΔfH |
−416.2 kJ·mol−1 |
| Hazards | |
| Safety data sheet | ICSC 1592 |
| Flash point | Not flammable |
| Lethal dose or concentration (LD, LC): | |
| LD50 (Median dose) |
570 mg/kg (oral, rat)[5] |
| US health exposure limits (NIOSH): | |
| PEL (Permissible) |
none[6] |
| REL (Recommended) |
TWA 2 mg/m3[6] |
| IDLH (Immediate danger) |
N.D.[6] |
| Related compounds | |
| Other anions |
Caesium oxide Cesium 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 | |
Cesium hydroxide (CsOH) is a chemical compound consisting of an ion of caesium and a hydroxide ion. It is a strong base (pKb=-1.76), much like the other 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 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.
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 although it is more reactive than they are.
Cesium hydroxide can be obtained by the following chemical reaction:
- 2 Cs + 2 H2O → 2 CsOH + H2
The above reaction occurs explosively with enough force to shatter a Pyrex beaker. Caesium metal will react with ice above −116 °C.
References
- ↑ http://www.inchem.org/documents/icsc/icsc/eics1592.htm
- ↑ Lide, David R. (1998), Handbook of Chemistry and Physics (87 ed.), Boca Raton, FL: CRC Press, pp. 4–51, ISBN 0-8493-0594-2
- ↑ http://www.periodensystem-online.de/index.php?show=list&id=acid&prop=pKb-Werte&sel=oz&el=92
- ↑ Lide, David R. (1998), Handbook of Chemistry and Physics (87 ed.), Boca Raton, FL: CRC Press, pp. 5–14, ISBN 0-8493-0594-2
- ↑ http://chem.sis.nlm.nih.gov/chemidplus/rn/21351-79-1
- 1 2 3 "NIOSH Pocket Guide to Chemical Hazards #0111". National Institute for Occupational Safety and Health (NIOSH).
External links
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