Detection of Nickel Atoms Released from Electrodes in Spark Discharges Using Laser-Induced Fluorescence.

The reduction of greenhouse gas emissions and the effort of carbon neutrality require the improvement of spark-ignition engines in terms of efficiency and capability to operate on renewable fuels. The electrode wear of spark plugs, used for ignition of novel fuels and lean mixtures, emerges as a significant challenge in this transition. Understanding the physical mechanism and influence of spark operation parameters of the wear process is thus important.

High-Pressure Synthesis of Metal-Inorganic Frameworks Hf N ⋅N , WN ⋅N , and Os N ⋅3 N with Polymeric Nitrogen Linkers.

Polynitrides are intrinsically thermodynamically unstable at ambient conditions and require peculiar synthetic approaches. Now, a one-step synthesis of metal-inorganic frameworks Hf N ⋅N , WN ⋅N , and Os N ⋅3 N via direct reactions between elements in a diamond anvil cell at pressures exceeding 100 GPa is reported. The porous frameworks (Hf N , WN , and Os N ) are built from transition-metal atoms linked either by polymeric polydiazenediyl (polyacetylene-like) nitrogen chains or through dinitrogen units.

Metastable silica high pressure polymorphs as structural proxies of deep Earth silicate melts.

Modelling of processes involving deep Earth liquids requires information on their structures and compression mechanisms. However, knowledge of the local structures of silicates and silica (SiO) melts at deep mantle conditions and of their densification mechanisms is still limited. Here we report the synthesis and characterization of metastable high-pressure silica phases, coesite-IV and coesite-V, using in situ single-crystal X-ray diffraction and ab initio simulations.

High-Pressure Synthesis of a Nitrogen-Rich Inclusion Compound ReN ⋅x N with Conjugated Polymeric Nitrogen Chains.

A nitrogen-rich compound, ReN ⋅x N , was synthesized by a direct reaction between rhenium and nitrogen at high pressure and high temperature in a laser-heated diamond anvil cell. Single-crystal X-ray diffraction revealed that the crystal structure, which is based on the ReN framework, has rectangular-shaped channels that accommodate nitrogen molecules. Thus, despite a very high synthesis pressure, exceeding 100 GPa, ReN ⋅x N is an inclusion compound.