Icosahedral Boron-Rich Solids

Boron‐rich molecules and solids hold a special place within chemistry. They do not follow the general bonding rules we are taught in chemistry classes. For example, some boron‐rich solids are composed of 12‐atom clusters of boron atoms in which each boron atom resides on a vertex of an icosahedron. These solids are very stable refractory materials with melting temperatures up to 2400 °C—a thousand degrees greater than silicon's. Beyond this, they possess numerous novel structural, electronic and thermal properties that are not only interesting but useful. The unusual three‐center bonding and unique crystal structures of these refractory materials produce many exceptional properties: Some compounds are, for example, very high‐temperature thermoelectrics.