Density functional theory calculations have been carried out to characterize the ground-state electronic structure of the recently synthesized sila-adamantane cluster, Si14C24H72, which represents the smallest repeat unit of bulk silicon lattice [J. Fischer et al., Science 310 (2005) 825]. The computed HOMO-LUMO gap (similar to 4.5 eV) and ionization potential (similar to 6.4 eV) along with a negative value of the electron affinity indicate that the cluster is exceptionally stable against both oxidation and reduction. The chemical functionalization of this cluster (with -OH groups) and the encapsulation of small ions (Li+, Na+, and F-) into its Silo cage have also been computationally explored. (c) 2006 Elsevier B.V. All rights reserved.