Caesium hydroxide
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| Names | |
|---|---|
| Other names
Caesium hydrate
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| Identifiers | |
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3D model (Jmol)
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| ChEBI | |
| ChemSpider | |
| ECHA InfoCard | 100.040.298 |
| EC Number | 244-344-1 |
| 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) |
| 300 g/100 mL at 30 °C | |
| Solubility | Soluble in ethanol |
| Basicity (pKb) | −0.8(CsOH(aq) = Cs+ + OH–) |
| Thermochemistry | |
| 69.9 J·mol−1·K−1 | |
|
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): | |
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LD50 (median dose)
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570 mg/kg (oral, rat) |
| US health exposure limits (NIOSH): | |
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PEL (Permissible)
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none |
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REL (Recommended)
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TWA 2 mg/m3 |
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IDLH (Immediate danger)
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N.D. |
| Related compounds | |
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Other anions
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Caesium oxide Caesium fluoride |
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Other cations
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Lithium hydroxide Sodium hydroxide Potassium hydroxide Rubidium hydroxide |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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 (what is   ?) |
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| Infobox references | |
Caesium 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.
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.
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