Pentaborane, also called pentaborane(9) to distinguish it from B5H11, is an inorganic compound with the formula B5H9. It is one of the most common boron hydride clusters, although it is a highly reactive compound. Because of its high reactivity toward oxygen, it was once evaluated as rocket or jet fuel. Like many of the smaller boron hydrides, pen... Found on http://en.wikipedia.org/wiki/Pentaborane