Ba2[Ir(OH)6](OH)2, orthorhombic, Pbca (no. 61), a = 8.5717(4) Å, b = 8.6814(4) Å, c = 10.3683(5) Å, V = 771.55(6) Å3, Z = 4, Rgt(F) = 0.0154, wRref(F2) = 0.0304, T = 100(2) K.

The reactions of ammonium perrhenate and pertechnetate in highly alkaline medium led to the isotypic mixed anionic nitridotrioxidorhenate and -technetate K-3[MO4][MO3N] (M= Tc, Re). Both compounds occur as colorless crystals, which were investigated by single crystal X-ray diffraction. Furthermore, K-3[ReO4][ReO3N] has been studied by means of X-ray photoelectron spectroscopy to determine the oxidation state of rhenium. The obtained results have been complemented by magnetic measurements. IR and Raman spectroscopy indicated the presence of Re-O as well as Re-N bonds.

The Cover Feature shows a 3D view of the single-crystal structure of K3[MO4][MO3N] with M=Tc, Re together with the Raman spectrum of K3[ReO4][ReO3N]. Both compounds were synthesized using a highly alkaline KOH hydroflux. Since single-crystal X-ray diffraction does not prove the presence of nitrogen within the (MO4)-tetrahedra unambiguously, Raman and IR spectroscopy as well as XPS and elemental analysis were conducted. Furthermore, magnetochemical measurements provide evidence for the diamagnetic behavior of the closed-shell heptavalent rhenium species and UV-Vis spectroscopy underpins the absence of mixed valences. The cover was designed by Dr. David van Gerven and Désirée Badea. More information can be found in the Research Article by J. Bruns and co-workers.

Lewis base-free lanthanoid (Ln) and actinoid (An) iodides are difficult to obtain, as standard protocols describe syntheses in solutions of donor solvents which are ultimately hard to remove. We have now established a mechanochemical approach towards the synthesis of Lewis base-free f-block metal iodides with excellent yields. In particular, we describe herein the synthesis of EuI2 as an example of a divalent lanthanoid iodide, of CeI3 as an example of a trivalent lanthanoid iodide, and of UI3 as the most important actinoid iodide. Each can be obtained in high yield with minimal work-up, presenting the most efficient and simple synthetic route to access these materials to date.

Abstract The preparation of novel technetium oxides, their characterization and the general investigation of technetium chemistry are of significant importance, since fundamental research has so far mainly focused on the group homologues. Whereas the structure chemistry of technetium in strongly oxidizing media is dominated by the TcO4- anion, our recent investigation yielded the new TcO3N2- anion. Brown single crystals of Ba[TcO3N] were obtained under hydrothermal conditions starting from Ba(OH)2 ⋅ 8H2O and NH4[TcO4] at 200 °C. Ba[TcO3N] crystallizes in the monoclinic crystal system with the space group P21/n (a=7.2159(4) Å, b=7.8536(5) Å, c=7.4931(4) Å and β=104.279(2)°). The crystal structure of Ba[TcO3N] consists of isolated TcO3N2- tetrahedra, which are surrounded by Ba2+ cations. XANES measurements complement the oxidation state +VII for technetium and Raman spectroscopic experiments on Ba[TcO3N] single crystals exhibit characteristic Tc−O and Tc−N vibrational modes.

Preparation of a catalyst for the ethylene oxide production requires impregnation of a porous corundum support with an aqueous silver ethylene diamine oxalate complex solution, to which among others NH4[ReO4] is added. Here we report on [Ag(mu-en)][ReO4] that precipitates from such a mixture. Single crystal structure analysis has revealed a striking similarity of the [Ag(mu-en)](+) entity with the same complex cation encountered in [Ag(mu-en)](2)(C2O4)x2H(2)O. Silver is coordinated end-on to the nitrogen atoms of the en ligands. The [ReO4](-) anions are not bonded to the silver cations, but instead involved in N-H center dot center dot center dot O hydrogen bonds to the ethylene diamine molecules. The first step of thermal degradation occurs at approximately the same temperature for both, the main component precipitate [Ag(mu-en)](2)(C2O4)x2H(2)O and [Ag(mu-en)][ReO4], warranting proximity of the rhenium promoter and the elemental silver deposit. At 300 degrees C, the temperature at which the catalyst for EO synthesis is commonly calcined, the decomposition product of plain [Ag(mu-en)][ReO4] under synthetic air is Ag[ReO4], in full analogy to industrial manufacturing process for selected Re-promoted EO catalyst formulations.