We report the synthesis, structure, and properties of novel bulk rhenium nitrides, hexagonal Re2N, and Re3N. Both phases have very high bulk moduli of >400\,\,GPa, similar to the most incompressible binary transition-metal (TM) carbides and nitrides found to date. However, in contrast to other incompressible TM carbides and nitrides, Re3N is better placed for potential technological applications, as it can be formed at relatively moderate pressures (13\char21{}16~GPa) and temperatures (1600\char21{}2400~K).

Achieving highly efficient phosphorescence in purely organic luminophors at room temperature remains a major challenge due to slow intersystem crossing (ISC) rates in combination with effective non‐radiative processes in those systems. Most room temperature phosphorescent (RTP) organic materials have O‐ or N‐lone pairs leading to low lying (n, π*) and (π, π*) excited states which accelerate k_isc through El‐Sayed's rule. Herein, we report the first persistent RTP with lifetimes up to 0.5 s from simple triarylboranes which have no lone pairs. RTP is only observed in the crystalline state and in highly doped PMMA films which are indicative of aggregation induced emission (AIE). Detailed crystal structure analysis suggested that intermolecular interactions are important for efficient RTP. Furthermore, photophysical studies of the isolated molecules in a frozen glass, in combination with DFT/MRCI calculations, show that (σ, B p)→(π, B p) transitions accelerate the ISC process. This work provides a new approach for the design of RTP materials without (n, π*) transitions.

Transition metal nitrides, carbides and borides have a high potential for industrial applications as they not only have a high melting point but are generally harder and less compressible than the pure metals. Here we summarize recent advances in the synthesis of binary transition metal nitrides, carbides and borides focusing on the reaction of the elements at extreme conditions generated within the laser-heated diamond anvil cell. The current knowledge of their structures and high-pressure properties like high-(p; T) stability, compressibility and hardness is described as obtained from experiments.

Raman scattering measurements and lattice-dynamics calculations were performed on magnesium tungstate (MgWO${}_4$) under high pressure up to 41 GPa. Experiments were carried out on a selection of pressure media. The influence of nonhydrostaticity on the structural properties of MgWO${}_4$ and isomorphic compounds is examined. Under quasihydrostatic conditions, a phase transition was found at 26 GPa in MgWO${}_4$. The high-pressure phase is tentatively assigned to a triclinic structure similar to that of CuWO${}_4$. We also report and discuss the Raman symmetries, frequencies, and pressure coefficients in the low- and high-pressure phases. In addition, the Raman frequencies for different wolframites are compared and the variation of the mode frequency with the reduced mass across the family is investigated. Finally, the accuracy of theoretical calculations is systematically discussed for MgWO${}_4$, MnWO${}_4$, FeWO${}_4$, CoWO${}_4$, NiWO${}_4$, ZnWO${}_4$, and CdWO${}_4$.