New Energetic\nDodecahydro-<i>closo</i>-Dodecaborates\n(N<sub>2</sub>H<sub>5</sub>)<sub>4</sub><i>X</i><sub>2</sub>[B<sub>12</sub>H<sub>12</sub>] (<i&g

Two new tetrahydrazinium dihalide dodecahydro-<i>closo</i>-dodecaborates (N<sub>2</sub>H<sub>5</sub>)<sub>4</sub><i>X</i><sub>2</sub>[B<sub>12</sub>H<sub>12</sub>] (<i>X</i><sup>–</sup> = Cl<sup>–</sup> and Br<sup>–</sup>)\nwere successfully synthesized via the direct reaction of dihydrazinium\ndodecahydro-<i>closo</i>-dodecaborate (N<sub>2</sub>H<sub>4</sub>)<sub>2</sub>[B<sub>12</sub>H<sub>12</sub>] with hydrazinium\nhalides (N<sub>2</sub>H<sub>5</sub>)Cl and (N<sub>2</sub>H<sub>5</sub>)Br in aqueous media. The resulting isotypic compounds crystallize\nmonoclinically in the space group <i>P</i>2<sub>1</sub>/<i>c</i> with similar unit-cell parameters (<i>a</i> =\n681.98(4) pm, <i>b</i> = 1025.38(6) pm, <i>c</i> = 1325.38(8) pm, and β = 98.393(3)° for the chloride\nand <i>a</i> = 686.05(4) pm, <i>b</i> = 1032.51(6)\npm, <i>c</i> = 1316.04(8), and β = 97.449(3)°\nfor the bromide). Their crystal structure was elucidated using single-crystal\nX-ray diffraction techniques, unveiling a new unique arrangement for\nthe composition <i>A</i><sub>4</sub><i>B</i><sub>2</sub><i>C</i> (<i>A</i> = hydrazinium, <i>B</i> = halide, and <i>C</i> = dodecahydro-<i>closo</i>-dodecaborate). This distinctive structural configuration\nsets it apart from compounds exhibiting other <i>A</i><sub>4</sub><i>B</i><sub>2</sub><i>C</i> arrangements,\nsuch as the spinel or double-perovskite structure type. In this new\nstructure, the halide anions are coordinated by five hydrazinium cations,\ncreating triangular bipyramidal polyhedra. These are interconnected\nvia edge- and corner-sharing, resulting in the formation of hexagonal\ntunnels along the [100] direction. Within each of these tunnels, the\n[B<sub>12</sub>H<sub>12</sub>]<sup>2–</sup> clusters reside\ncentrally located. Differential scanning calorimetry analyses demonstrate\nthat these compounds contain a substantial amount of energy that is\nreleased during their thermal decomposition.