(Phys.org)—The pentazole molecule and its anion, cyclo-N5- has proven elusive to researchers for almost a century. The pentazole anion is highly unstable and cannot be made in bulk. Researchers from Nanjing University of Science and Technology and the University of Science and Technology Liaoning have devised a synthesis of a salt containing the pentazole anion that is stable up to 117oC. Their report appears in Science.