10.1021/ja8077522.s003 Thomas M. Klapötke Thomas M. Klapötke Jörg Stierstorfer Jörg Stierstorfer The CN<sub>7</sub><sup>−</sup> Anion American Chemical Society 2009 multinuclear NMR spectroscopy velocity Ddet mass spectrometry Raman spectroscopy tetrazole salts metal salts CBS scanning calorimetry CN impulse Isp IR 2009-01-28 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/The_CN_sub_7_sub_sup_sup_Anion/2882629 Several salts containing the CN<sub>7</sub><sup>−</sup> anion were prepared by deprotonation of 5-azido-1<i>H</i>-tetrazole (<b>1</b>). The highly explosive compounds hydrazinium (<b>2</b>), ammonium (<b>3</b>), aminoguanidinium (<b>4</b>), guanidinium (<b>5</b>), lithium (<b>6</b>), sodium (<b>7</b>), potassium (<b>8</b>), cesium (<b>9</b>), and calcium (<b>10</b>) azidotetrazolate were characterized by low temperature single X-ray diffraction. Other analytic methods, such as IR and Raman spectroscopy, multinuclear NMR spectroscopy, mass spectrometry, and differential scanning calorimetry were performed when possible since some of the metal salts explode spontaneously. <b>2</b> contains the highest nitrogen content (87.48%) of all known tetrazole salts. The impact, friction, and electrical spark sensitivity of <b>2</b>, <b>3</b>, <b>4</b>, and <b>5</b> were measured, resulting in values which belong to primary explosives. In addition, the heats of formation of <b>2</b>, <b>3</b>, and <b>4</b> were calculated using the CBS-4M level of quantum mechanical theory. These, in turn, were used to estimate detonation pressure <i>p</i><sub>C-J</sub> and velocity <i>D</i><sub>det</sub> as well as the specific impulse <i>I</i><sub>sp</sub>.