Diborane
Original archive entry. The text, images and links below are kept as they were written.
Boron 'zip' fuels were much in fashion in the late 1950's. They seemed to offer a means of boosting the performance of both aircraft (the B-70 bomber) and rockets. However expense, toxicity, and fouling of engines led to them being abandoned.
Diborane (B2H6) is the simplest hydride of boron. Of all the boron hydrides, diborane is the most easily prepared in pure form. Diborane is a colorless gas in its normal state, exhibiting a sweet odor. It hydrolyses in water to yield boric acid and hydrogen. It is soluble in carbon disulfide, and reacts slowly with bromine. Diborane reacts with any oxidized surface as a strong reducing agent. It should be stored at temperatures below 20 deg C, and will decompose slowly during storage. At temperatures of approximately 100 deg C, diborane decomposes into hydrogen, tetra-borane, pentaborane, and solids. It is an extremely toxic propellant.