In chemistry, boranes comprise a large group of compounds with the generic formula of B_xH_y. These compounds do not occur in nature. Many of the boranes readily oxidise on contact with air, some violently. The class is named after the parent chemical called "borane" itself, chemical formula BH₃. This compound is only known to exist as a transient intermediate since it dimerises to form diborane, B₂H₆. The larger boranes all consist of boron clusters that are polyhedral. In addition to the charge-neutral boranes, a large number of anionic boron hydrides are known. The most important boranes are diborane B₂H₆ and two of its pyrolysis products, pentaborane B₅H₉ and decaborane B₁₀H₁₄. The development of the chemistry of boron hydrides led to new experimental techniques and theoretical concepts. Boron hydrides have been studied as potential fuels, for rockets and for automotive uses, but the only commercial applications involve derivatives of borane.