Caesium hydroxide
| Caesium hydroxide | |
|---|---|
| Identifiers | |
| CAS number | [] |
| UN number | 2682 |
| RTECS | FK9800000 |
| Properties | |
| Chemical formula | CsOH |
| Molar mass | 149.912 g/mol |
| Appearance | whitish-yellow deliquescent crystals |
| Density | 3.675 g/cm3, solid |
| Melting point |
342.3°C |
| Solubility in water | 300 g/100 ml at 30°C |
| Solubility | soluble in ethanol[1] |
| Basicity (pKb) | 1.76 |
| Structure | |
| Thermochemistry | |
| Std enthalpy of formation ΔfH |
−416.2 kJ·mol-1 |
| Standard molar entropy S |
104.2 J·K−1·mol−1 |
| Specific heat capacity C | 69.9 J·mol-1·K-1[2] |
| Hazards | |
| Material safety data sheet (MSDS) | ICSC 1592 |
| EU index number | Not listed |
| Flash point | Non flammable |
| Related compounds | |
| Other anions | Caesium oxide Caesium fluoride |
| Other cations | Lithium hydroxide Sodium hydroxide Potassium hydroxide Rubidium hydroxide |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) | |
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, much like 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 hydoxide is typically a hydrate.
It is an anisotropic etchant of silicon, exposing 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.
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:
- 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
External links
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