Caesium dodecaborate
From Wikipedia, the free encyclopedia
| Caesium dodecaborate | |
|---|---|
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| IUPAC name | Caesium dodecaborate |
| Identifiers | |
| CAS number | [149-57-5] |
| Properties | |
| Molar mass | 407.61.21 g/mol |
| Appearance | Colourless solid |
| Melting point |
>650 °C |
| Solubility in water | low |
| Solubility | good in ethers |
| Hazards | |
| Main hazards | flammable |
| Related compounds | |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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Caesium dodecarborate is an inorganic compound with the formula Cs2B12H12. It is a salt, with caesium cations and [B12H12]2- anions.
Contents |
[edit] Structure
The anion has a icosahedral shape, belonging to the point group symmetry Ih. Its icosahedral shape is consistent with the classification of this cage as "closo."
Crystals of Cs2B12H12 feature Cs+ ions in contact with twelve hydrides provided by four B12H122-. The B-B bond distances are 178 pm, and the B-H distances are 112 pm.[1] Many other salts are known.[2]
[edit] Preparation
It is prepared in two steps from sodium borohydride. First the borohydride is converted into a triborate anion using the etherate of boron trifluoride:
- 4 NaBH4 + BF3 → NaB3H8 + 3 NaF + 4 H2
Pyrolysis of the triborate gives the twelve boron cluster as the sodium salt, which is then treated with caesium hydroxide to precipitate Cs2B12H12.
[edit] Applications
Salts of B12H122- have been investigated for neutron-capture therapy and as fuels for airbags.[3]
Salts of B12H122- are precursors to related derivatives including B12(OH)122- and B12(CH3)122-. This closo boron hydride resists degradation more so than the isoelectronic carboranes.
[edit] References
- ^ Ioannis Tiritiris, Thomas Schleid, Klaus Müller, Wilhelm Preetz “Strukturelle Untersuchungen an Cs2[B12H12]” Zeitschrift für anorganische und allgemeine Chemie 2000, Volume 626, Issue 2, pp. 323-325.
- ^ Ioannis Tiritiris, Nguyen-Duc Van, Thomas Schleid “Synthesis and Crystal Structure of [Ni(H2O)6][B12H12]·6 H2O” Zeitschrift für anorganische und allgemeine Chemie 2004, Volume 630, Issue 11 pp 1763. DOI: 10.1002/zaac.200470138.
- ^ Igor B. Sivaev, Vladimir I. Bregadze, and Stefan Sjoberg “Chemistry of closo-Dodecaborate Anion [B12H12]2-: A Review” Collection of Czechoslovak Chemical Communications 2002, 67(6), 679-727. doi:10.1135/cccc20020679.
