Bottles, glass tubes and solvents are commonly found in chemical laboratories and industry. Chemistry using solvent or liquid-based materials is the traditional method of synthesis. Although very efficient, the unavoidable question is how to recycle the solvent safely and environmentally. The simplest answer is solvent-free chemistry, but how do you get a chemical reaction to occur without using a solvent?
In 1820, Michael Faraday delivered his idea using pure force. In this idea, mortar grinding was used to induce the mechanical reduction of His AgCl by Zn, Sn, Fe and Cu. This is probably the first experiment in so-called mechanochemistry. By definition, mechanochemistry directly converts mechanical energy into chemical energy or chemical potential. Mechanical milling is the most common method of performing mechanochemistry. However, many materials are chemically stable under such mild mechanical processes due to the limited strength of hand polishing. Here, a collaborative study involving Yantai University, HPSTAR, Linyi University, ESRF, and California State University Northbridge used a pair of diamonds to compress AgI powders to a very high pressure, equivalent to 420,000 atm. increase. They observed that AgI decomposes into Ag and I base members.
Mr. Jianfu Li of Yantai University said: “No chemical reaction occurs from ordinary crystals to superionic solids. However, if the pressure is increased sufficiently, both Ag and I ions are recruited and begin to react.”
High-pressure experiments are performed at the European Synchrotron Radiation Facility and allow scientists to use high-energy focused X-rays to measure the structure of samples under such pressurized conditions. They clearly confirmed the disappearance of AgI solids and the appearance of Ag and I. HPSTAR staff scientist Qingyang Hu added, “This pressure-induced chemistry should also occur in other ionic solids, such as AgCl and AgBr, but at much higher pressures.”
This experiment was pioneered by computational modeling that predicts the evolution of Ag-I bonds and their properties under high pressure. “Through a so-called structure search algorithm, we can predict stable AgI structures under appropriate pressure conditions, which is another example of the power of this algorithm,” explained Professor Xiaoli Wang. “By tracing the ionic properties of AgI, each step of this mechanochemistry is theoretically validated and fully demonstrated experimentally. Our computational approach has the potential to design new pathways for chemical reactions.” I have.”
