Synthesis and Stability of High-Energy-Density Niobium Nitrides under High-Pressure Conditions.

High-energy-density materials (HEDMs) are crucial in various applications, from energy storage to defense technologies. Transition metal polynitrides are promising candidates for HEDMs. Using single-crystal synchrotron X-ray diffraction, we investigated the crystal structures of niobium nitride, specifically NbN and NbN, under high-pressure conditions of up to 86 GPa.

Photoluminescent chain-of-dimer anion in a novel hybrid halometallate (CHN){SbBr}: atypical behavior in one-dimensional anionic systems.

In pursuit of identifying less toxic hybrid compounds suitable for optoelectronic applications, we synthesized a novel homopiperazinium bromoantimonate(III), (CHN){SbBr}. It readily crystallized from an aqueous hydrobromic acid solution and was found to be stable both in air and upon heating up to 175 °C. The crystal structure of the new bromoantimonate(III) consisted of {SbBr} zigzag chains, which were composed of strongly trigonally distorted SbBr octahedral anions and CHN dications.

Ca[CO][CO] is a pyrocarbonate which can be formed at p, T-conditions prevalent in the Earth's transition zone.

Understanding the fate of subducted carbonates is a prerequisite for the elucidation of the Earth's deep carbon cycle. Here we show that the concomitant presence of Ca[CO] with CO in a subducting slab very likely results in the formation of an anhydrous mixed pyrocarbonate, , at moderate pressure ( ≈ 20 GPa) and temperature ( ≈ 1500 K) conditions. We show that at these conditions can be obtained by reacting Ca[CO] with CO in a laser-heated diamond anvil cell.

6-Fold-Coordinated Beryllium in Calcite-Type Be[CO].

The anhydrous beryllium carbonate Be[CO] with calcite-type crystal structure was obtained by a reaction of BeO with CO in a laser-heated diamond anvil cell at pressures between 30 GPa and 80 GPa and elevated temperatures. Its calcite-type crystal structure (3̅ with = 6) is characterized by 6-fold-coordinated beryllium atoms forming [BeO] octahedra and by trigonal-planar [CO] groups. The crystal structure was determined by synchrotron-based single-crystal X-ray diffraction and confirmed by density-functional-theory-based calculations in combination with experimental Raman spectroscopy.