High Pressure and Chemical Bonding in Materials Chemistry

Abstract

Materials chemistry under high pressures is an important research area opening new routes for stabilizing novel materials or original structures with different compositions (oxides, oxoborates, nitrides, nitridophosphates, sulfides,...).Due to the varieties of chemical compositions and structures involved, high pressure technology is also an important tool for improving the investigations on chemical bonding and consequently the induced physico-chemical properties.Two different approaches can be described: (i) the chemical bond is pre-existing and in such a case, high pressures lead to structural transformations, (ii) the chemical bond does not exist and high pressures are able to help the synthesis of novel materials. In both cases the condensation effect (∆V < 0 between precursors and the final product) is the general rule. In addition, through the improvement of the reactivity, high pressures can lead to materials that are not reachable through other chemical routes.

Quantifying magnetic exchange in doubly-bridged Cu–X2–Cu (X = F, Cl, Br) chains enabled by solid state synthesis of CuF2(pyrazine)

“…High pressure has increasingly been used as a synthetic enabler for the discovery of new inorganic compounds and for polymorph stabilization in pharmaceutical materials and molecular crystals. 11 We demonstrate that pressure can be used to prepare new coordination polymers through solid state reactions. Highly-pure CuF 2 (pyz) was synthesized by pressing a pellet composed of a 1 : 1 powder of anhydrous CuF 2 and pyrazine under B4 GPa of pressure at a temperature of 100 1C for several hours.…”

Selective Separation of Toluene/n‐Heptane by Supported Ionic Liquid Membranes with [Bmim][BF4]

“…Special interest of experimental and theoretical research groups is motivated by the frequent occurrence of superconducting properties in binary phases of metals with group IV elements. The phenomenon is associated to the well‐known effect of elevated pressure6–8 to stabilize phases with increased coordination numbers of the atoms. In networks of tetrel‐rich high‐pressure compounds, up to eight short Si–Si and Ge–Ge contacts9,10 have been observed.…”

Temperature and pressure effects on C112S azurin: Volume, expansivity, and flexibility changes

“…Instead, the response of proteins to pressure and the volumetric changes that occur upon unfolding have yet to be extensively characterized. If we compare the energy passed by high pressure with the average value of the energy of the chemical bonds it is clear that pressure is a mild perturbation and it can only affect weak chemical bonds. Covalent bonds participating in the protein primary structure are pressure insensitive at least up to pressure values of 1000–1500 MPa .…”