The stability of the crystalline phase of a cluster-assembled solid K(
Al-13) has been investigated using first-principles total energy calcu
lations. We find that K(Al-13) may form in the CsCl structure with a l
attice constant of 6.52 Angstrom. Unlike the gas phase, in which the g
round state of the Al-13 cluster is icosahedral, the Al,, becomes cubo
ctahedral in the solid phase due to crystal field effects. The system
is metallic and is stable against lattice distortions. The calculation
s suggest that a new metastable solid could be made from two immiscibl
e elements through specially designed synthesis processes.