Pentazenium
In chemistry, the pentazenium cation (also known as pentanitrogen) is a positively-charged polyatomic ion with the chemical formula N+5 and structure N−N−N−N−N. Together with solid nitrogen polymers and the azide anion, it is one of only three poly-nitrogen species obtained in bulk quantities. == History == Within the High Energy Density Matter research program, run by the U.S. Air Force since 1986, systematic attempts to approach polynitrogen compounds began in 1998, when Air Force Research Laboratory at Edwards AFB became interested in researching alternatives to the highly toxic hydrazine-based rocket fuel and simultaneously funded several such proposals.