of K(Al13)

The stability of the crystalline phase of a cluster-assembled solid K(AI~3) has been investigated using first-principles total energy calculations. We find that K(AIt3) may form in the CsC1 structure with a lattice constant of 6.52.~. Unlike the gas phase, in which the ground state of the All3 cluster is icosahedral, the AI]3 becomes cuboctahedral in the solid phase due to crystal field effects. The system is metallic and is stable against lattice distortions. The calculations uggest hat a new metastable solid could be made from two immiscible lements through specially designed synthesis processes. In recent years, research on atomic clusters has added a new dimension to materials cience, provid-ing opportunities to make novel materials with un-usual properties. It is now possible to not only make specific clusters in the gas phase but also to assem-ble them into solids not found in nature. The best-known example is the discovery of various crys-talline phases that incorporate C60 [1]. In this Letter, we present powerful evidence for another type o