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 TcO 4 ½ � À anion, our recent investigation yielded the new TcO 3 N ½ � 2À anion. Brown single crystals of Ba[TcO 3 N] were obtained under hydrothermal conditions starting from Ba(OH) 2 • 8H 2 O and NH 4 [TcO 4 ] at 200 °C. Ba½TcO 3 N� crystallizes in the monoclinic crystal system with the space group P2 1 /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 Ba½TcO 3 N� consists of isolated TcO 3 N ½ � 2À tetrahedra, which are surrounded by Ba 2 + cations. XANES measurements complement the oxidation state + VII for technetium and Raman spectroscopic experiments on Ba[TcO 3 N] single crystals exhibit characteristic TcÀ O and TcÀ N vibrational modes.

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.

The reactions of ammonium perrhenate and pertechnetate in highly alkaline medium led to the isotypic mixed anionic nitridotrioxidorhenate and ‐technetate K3[MO4][MO3N] (M= Tc, Re). Both compounds occur as colorless crystals, which were investigated by single crystal X‐ray diffraction. Furthermore, K3[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.

Ethylene oxide (EO) is produced by catalytic gas phase oxidation of ethylene with oxygen. Preparation of the corundum supported silver catalyst is of high complexity due to large number of components and sophisticated steps of processing. The cover picture highlights our study on tracking the fate of the rhenium based additive, which constitutes an essential promoter of the catalyst, from the starting compound (NH4)[ReO4], through the primary precipitate [Ag(μ‐en)][ReO4] forming from the complex solution after impregnation of the support and finally the stages of thermal decomposition. Preparation, crystal structure and thermal behavior of the intermediate [Ag(μ‐en)][ReO4] are providing a relevant piece to the complex mosaic of the heterogeneous EO catalyst. (DOI: 10.1002/zaac.202200267)

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(μ‐en)][ReO4] that precipitates from such a mixture. Single crystal structure analysis has revealed a striking similarity of the [Ag(μ‐en)]+ entity with the same complex cation encountered in [Ag(μ‐en)]2(C2O4)×2H2O. 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⋅⋅⋅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(μ‐en)]2(C2O4)×2H2O and [Ag(μ‐en)][ReO4], warranting proximity of the rhenium promoter and the elemental silver deposit. At 300 °C, the temperature at which the catalyst for EO synthesis is commonly calcined, the decomposition product of plain [Ag(μ‐en)][ReO4] under synthetic air is Ag[ReO4], in full analogy to industrial manufacturing process for selected Re‐promoted EO catalyst formulations.