Abstract1,1‐Diamino‐2,2‐dinitroethene, C2H4N4O4 (FOX‐7), is a novel high energy density material with low friction and impact sensitivity and a high activation barrier to detonation. In this study, the previously unknown crystal structure of the γ‐polymorph of trimorphic FOX‐7 is reported. γ‐FOX‐7 is stable from ∼435 K until the compound decomposes just above 504 K. A single crystal of α‐FOX‐7 (P21/n, Z=4, a=694.67(7) pm, b=668.87(9) pm, c=1135.1(1) pm, β=90.14(1)°, T=373 K) was first transformed into a single crystal of β‐FOX‐7 (P212121, Z=4, a=698.6(1) pm, b=668.6(2) pm, c=1168.7(3) pm, T=423 K) and then into a single crystal of γ‐FOX‐7 at 450 K. The γ‐FOX‐7 crystal was then subsequently quenched to 200 K. The structure of γ‐FOX‐7 (P21/n, Z=8, a=1335.4(3) pm, b=689.5(1) pm, c=1205.0(2) pm, β=111.102(8)°, T=200 K) consists of four planar layers, each containing two crystallographically independent FOX‐7 molecules found in the asymmetric unit.

A one-pot synthesis of various symmetrical and unsymmetrical 2-pyridyl-, 2-bromo-5-pyridyl-, and 2,5-dibromo-3-pyridyltellurium compounds has been carried out, at room temperature, by selective single bromine-magnesium exchange of 2-bromo-, 2,5-dibromo-and 2,3,5-tribromopyridine, respectively, with isopropylmagnesium chloride. This exchange reaction gives the corresponding pyridylmagnesium chlorides, which, upon insertion of elemental tellurium (activated), give the pyridyltelluromagnesium chlorides, and,

More stable than it seems: The binary uranium–nitrogen anion U(N3)73− was synthesized and characterized as the (Bu4N)3[U(N3)7] salt. The U(N3)73− ion is the first structurally characterized heptaazide and is the first homoleptic azide of an actinide. The crystal structure shows a pentagonal‐bipyramidal arrangement of the azide ligands around the central uranium(IV) atom (see structure; N: blue; U: green).

The synthesis and characterization of the neutral uranylisocyanate UO(2)(NCO)(2)(OP(NMe(2))(3))(2) [crystal data: monoclinic, P2(1)/c, a = 8.512(2) A, b = 10.931(2) A, c = 14.329(3) A, beta = 103.923(3) degrees , V = 1294.0(4) A(3), Z = 2] and isocyanato uranate (Et(4)N)(6)[(UO(2))(2)(NCO)(5)O](2) x 2CH(3)CN x H(2)O [crystal data: monoclinic, P2(1)/c, a = 17.2787(2) A, b = 15.560(1) A, c = 32.7619(4) A, beta = 94.0849(5) degrees , V = 8786.5(2) A(3), Z = 4] are reported. Not only are these compounds the first unambiguously characterized uranium isocyanates regardless of the oxidation state for uranium, but they are also the first structurally characterized actinide isocyanates. Both compounds show coordination of the OCN moiety through nitrogen to uranium and were characterized using IR and (1)H, (13)C, (14)N, and (31)P NMR spectroscopy and X-ray diffraction.

In this contribution, the synthesis and structural characterization of the 4,5-dicyano-1,2,3-triazolate anion in its sodium, ammonium, guanidinium, aminoguanidinium, diaminoguanidinium, and triaminoguanidinium salts is reported. The synthesis of 4,5-dicyano-2H-triazole (1) was repeated as described in the literature (Johansson, P. et al. Solid State Ionics 2003, 156, 129) and spectroscopically characterized using (1)H, (13)C, and (15)N NMR, IR, and Raman spectroscopy, as well as differential scanning calorimetry (DSC) and mass spectrometry (DEI+). The molecular structure was determined for the first time using X-ray diffraction (1: monoclinic, P2(1)/c, a = 6.0162(6) A, b = 11.2171(10) A, c = 7.5625(7) A, beta = 94.214(8) degrees, V = 508.97(8) A(3), Z = 4). Compound 1 was deprotonated using Na(2)CO(3) to form the corresponding sodium salt of the 4,5-dicyano-1,2,3-triazolate anion (2) as a monohydrate. This compound was also characterized using (13)C, (14)N, (15)N NMR, IR, and Raman spectroscopy, as well as single crystal X-ray diffraction (2: monoclinic, P2(1)/c, a = 3.6767(6) A, b = 20.469(4) A, c = 9.6223(13) A, beta = 97.355(13) degrees, V = 718.2(2) A(3), Z = 4). Reaction of 2 with AgNO(3) yielded silver 4,5-dicyano-1,2,3-triazolate (3) which was characterized using IR and Raman spectroscopy, as well as DSC, and was used to prepare the ammonium (4), guanidinium (5), aminoguanidinium (6), diaminoguanidinium (7), and triaminoguanidinium (8) salts of the 4,5-dicyano-1,2,3-triazolate anion in a metathetical reaction from the corresponding ammonium and guanidinium halides. All new compounds (4-8) were spectroscopically characterized ((1)H and (13)C NMR, IR, Raman), the stabilities investigated using DSC, the mass spectra obtained using the FAB+ and FAB- methods and the solid state structures determined using single crystal X-ray diffraction: (4): orthorhombic, Pnma, a = 6.5646(13) A, b = 7.5707(16) A, c = 13.303(3) A, V = 661.1(2) A(3), Z = 4; (5): monoclinic, Cc, a = 12.6000(11) A, b = 17.1138(15) A, c = 12.0952(9) A, beta = 106.098(7) degrees, V = 2505.9(4) A(3), Z = 12; (6): monoclinic, Pa, a = 7.0921(9) A, b = 7.2893(9) A, c = 8.8671(11) A, beta = 105.141(11) degrees, V = 442.48(10) A(3), Z = 2; (7): monoclinic, P2(1), a = 3.7727(4) A, b = 15.6832(17) A, c = 8.3416(10) A, beta = 101.797(10) degrees, V = 483.13(9) A(3), Z = 2; (8): monoclinic, C2/c, a = 14.0789(14) A, b = 11.5790(11) A, c = 13.5840(14) A, beta = 115.239(10) degrees, V = 2003.1(3) A(3), Z = 8. The impact and friction sensitivities of compounds 4-8 were investigated using drop hammer and friction apparatus methods, and all compounds were found to be neither impact (> 30 J) nor friction sensitive (> 360 N). The detonation parameters of compounds 5- 8 were computed using the EXPLO5 code.

The synthesis and characterization of the dioxouranium(VI) dibromide and iodide hydrates, UO(2)Br(2)x3H(2)O (1), [UO(2)Br(2)(OH(2))(2)](2) (2), and UO(2)I(2)x2H(2)Ox4Et(2)O (3), are reported. Moreover, adducts of UO(2)I(2) and UO(2)Br(2) with large, bulky OP(NMe(2))(3) and OPPh(3) ligands such as UO(2)I(2)(OP(NMe(2))(3))(2) (4), UO(2)Br(2)(OP(NMe(2))(3))(2) (5), and UO(2)I(2)(OPPh(3))(2)(6) are discussed. The structures of the following compounds were determined using single-crystal X-ray diffraction techniques: (1) monoclinic, P2(1)/c, a = 9.7376(8) A, b = 6.5471(5) A, c = 12.817(1) A, beta = 94.104(1) degrees , V = 815.0(1) A(3), Z = 4; (2) monoclinic, P2(1)/c, a = 6.0568(7) A, b = 10.5117(9) A, c = 10.362(1) A, beta = 99.62(1) degrees , V = 650.5(1) A(3), Z = 2; (4) tetragonal, P4(1)2(1)2, a = 10.6519(3) A, b = 10.6519(3) A, c = 24.0758(6) A, V = 2731.7(1) A(3), Z = 4; (5) tetragonal, P4(1)2(1)2, a = 10.4645(1) A, b = 10.4645(1) A, c = 23.7805(3) A, V = 2604.10(5) A(3), Z = 4, and (6) monoclinic, P2(1)/c, a = 9.6543(1) A, b = 18.8968(3) A, c = 10.9042(2) A, beta =115.2134(5) degrees , V = 1783.01(5) A(3), Z = 2. Whereas 1 and 2 are the first UO(2)Br(2) hydrates and the last missing members of the UO(2)X(2) hydrate (X = Cl --> I) series to be structurally characterized, 4 and 6 contain room-temperature stable U(VI)-I bonds with 4 being the first structurally characterized room temperature stable U(VI)-I compound which can be conveniently prepared on a gram scale in quantitative yield. The synthesis and characterization of 5 using an analogous halogen exchange reaction to that used for the preparation of 4 is also reported.

By virtue of our recently established relationships, knowledge of the formula unit volume, V(m), of a solid ionic material permits estimation of thermodynamic properties such as standard entropy, lattice potential energy, and, hence, enthalpy and Gibbs energy changes for reactions. Accordingly, development of an approach to obtain currently unavailable ion volumes can expose compounds containing these ions to thermodynamic scrutiny, such as predictions regarding stability and synthesis. The isomegethic rule, introduced in this paper, states that the formula unit volumes, V(m), of isomeric ionic salts are approximately the same; this rule then forms the basis for a powerful and successful means of predicting unknown ion volumes (as well as providing a means of validating existing volume and density data) and, thereby, providing solid state thermodynamic data. The rule is exploited to generate unknown ion and (by additivity) corresponding formula unit volumes.

The reaction of cyanogen (NC-CN) with MN(3) (M=Na, K) in liquid SO(2) leads to the formation of the 5-cyanotetrazolate anion as the monohemihydrate sodium (1·1.5 H(2)O) and potassium (2) salts, respectively. Both 1·1.5 H(2)O and 2 were used as starting materials for the synthesis of a new family of nitrogen-rich salts containing the 5-cyanotetrazolate anion and nitrogen-rich cations, namely ammonium (3), hydrazinium (4), semicarbazidium (5), guanidinium (6), aminoguanidinium (7), diaminoguanidinium (8), and triaminoguanidinium (9). Compounds 1-9 were synthesised in good yields and characterised by using analytical and spectroscopic methods. In addition, the crystal structures of 1·1.5 H(2)O, 2, 3, 5, 6, and 9·H(2)O were determined by using low-temperature single-crystal X-ray diffraction. An insight into the hydrogen bonding in the solid state is described in terms of graph-set analysis. Differential scanning calorimetry and sensitivity tests were used to assess the thermal stability and sensitivity against impact and friction of the materials, respectively. For the assessment of the energetic character of the nitrogen-rich salts 3-9, quantum chemical methods were used to determine the constant volume energies of combustion, and these values were used to calculate the detonation velocity and pressure of the salts using the EXPLO5 computer code. Additionally, the performances of formulations of the new compounds with ammonium nitrate and ammonium dinitramide were also predicted. Lastly, the ICT code was used to determine the gases and heats of explosion released upon decomposition of the 5-cyanotetrazolate salts.