Silicon subiodide clusters (Si(n)I(m), n = 1-20) produced by laser ablation of bulk powder silicone tetraiodide have been investigated by time-of-flight mass spectroscopy and ab initio calculations. Both experimental results and theoretical calculations revealed a tendency to form different structures of the clusters depending on n: chain, ring, and cage structures for n < or = 6, 6 < n < 16, and n > or = 16, respectively. The results showed that iodine, like hydrogen, can be used for stable silicon cluster termination.