Among the characteristics of cesium, a soft, silvery-white alkali metal, is low electronegativity, i.e., the ability to take electrons from atoms of other elements. For that reason, lithium takes electrons from cesium under normal conditions, but under high pressure conditions change, leading to cesium taking electrons from lithium. Thanks to this fact, scientists from Skoltech and Jiangsu Normal University have managed to obtain four new substances, two of which – Li14Cs and Li6Cs – have a rare crystalline structure.
Based on the authors’ calculations, the newly-discovered compounds are superconductors: they lose electrical resistance when negative temperatures fall below the range from minus 213 to minus 223 degrees Celsius. In the future, these compounds could be suitable for creating high-performance microchips, high-power electromagnets for magnetic levitation trains, and thermonuclear fusion reactors.
“Needless to say, in terms of critical temperature, the superconductors from our study are clearly inferior to polyhydrides, which are compounds of certain metals and hydrogen with a high content of the latter. Nevertheless, our study gives a deeper understanding of the chemistry of lithium, other compounds of which – let’s call them lithiumides, although it is not yet clear if they exist – could be of interest in terms of superconductivity,” Artem Oganov, one of the authors of the study and doctor of physical and mathematical sciences, is quoted as saying by Skoltech.
The scientists believe that the lithium atom is very similar to hydrogen, which is why it could replace it in compounds similar to polyhydrides. Akin to hydrogen, lithium has one valence electron and is also one of the lightest elements, which is good for superconductivity: the lower the mass of the atom, the higher the critical temperature of the corresponding superconductor.
