Bonding rethink called for as new metavalent bond proposed
One of the most basic facts that chemistry students learn is the distinct types of chemical bond in solid-state materials: covalent, ionic and metallic, as well as curiosities such as hydrogen bonding. But if a proposal in two recent papers holds up, they will soon need to be taught about another class: the metavalent bond.
According toProf. Matthias Wuttig of the RWTH Aachen University in Germany and his co-workers, this kind of bonding is found in combinations of elements in and bordering the metalloid region of the periodic table, such as germanium, tin and lead tellurides. Compounds of this sort, they say, represent a distinct category of material, somewhat similar to metals in having an appreciable electrical conductivity but with a degree of electron-sharing like covalent compounds.