Decaborane

Decaborane, also called decaborane(14) or decaboron tetradecahydride, is a stable crystalline borane with chemical formula B₁₀H₁₄. It forms colorless to white crystals. The B₁₀ framework is an incomplete icosahedron.

B₁₀H₁₄ possesses a strong penetrating musty odor that is unique to boranes and quickly recognizable; decaborane itself smells intensely bitter, chocolate-like. When ignited it produces a bright green flame, as do other boron hydrides. It is not sensitive to moist air, although it hydrolyzes in boiling water, releasing hydrogen and boric acid solution. It is soluble in cold water.

Additional recommended knowledge

Essential Laboratory Skills Guide

What is the Correct Way to Check Repeatability in Balances?

Recognize and detect the effects of electrostatic charges on your balance

Synthesis

It is commonly synthesized via the pyrolysis of smaller boron hydride clusters (for example B₂H₆ or B₅H₉) under vacuum. The physical characteristics of decaborane(14) resemble those of the organic compounds naphthalene and anthracene, in that it is highly flammable and can be sublimed under vacuum at moderate temperatures. Sublimation is the most common method of purification.

Chemical properties

Decaborane(14) is soluble in a wide variety of non-polar and moderately polar solvents including hexanes, benzene, toluene, diethyl ether, and methylene chloride. In strongly coordinating solvents (i.e. CH₃CN or Me₂S), decaborane(14) readily forms an adduct with the formula B₁₀H₁₂•2L, where L = CH₃CN, Me₂S).

Decaborane(14) is a Brønsted acid: in the presence of moderately strong bases, a proton can be removed to generate the anion [B₁₀H₁₃]^–.

Decaborane, like pentaborane, is a powerful toxin affecting central nervous system, although considerably less toxic than pentaborane. It can be absorbed through skin.

It forms an explosive mixture with tetrachloromethane, which caused an often quoted explosion in a Malta, NY manufacturing facility in 1948 when CCl₄ was used to clean the equipment.^[1]

Applications

Decaborane ions can be used for low energy ion implantation of boron in the manufacture of semiconductors; the molecule decomposes in the plasma, yielding monoatomic boron ions. It is also used in plasma-assisted chemical vapor deposition to manufacture boron-containing thin films.

In fusion research, the absorbing nature of thin films of decaborane is used to boronize the walls of the tokamak vacuum vessel to reduce recycling of particles and impurities into the plasma and improve overall performance. [2]

In polymer chemistry, decaborane is used as a catalyst.^{[citation needed]}

Decaborane was also being used as an additive to special high-performance rocket fuels. Its derivates were investigated as well, eg. ethyl decaborane. One patented fuel composition includes vinyl decaborane-polyester copolymer. Vinyl decaborane ("dekene") is prepared by reacting decaborane with acetylene. [3]

See also

• Decaborane(16)

References

1. ^ UCLA, Condensed version of the 79th Faculty Research Lecture Presented by Professor M. Frederick Hawthorne, accessed 23 Oct 2006.

• NIST Chemistry Webbook, decaborane, accessed 23 Oct 2006.
• National Pollutant Inventory, Boron and compounds, accessed 23 Oct 2006.
• Decaborane in Organic Synthesis
• Webelements, Compounds of boron, accessed 23 Oct 2006.