Researchers have discovered a silicon cluster larger than four atoms. The team, comprising scientists from the University of Notre Dame in Indiana, may lead to a silicon nanoparticle solution that could have valuable optical properties. This apparently is the first time silicon clusters of this size have been extracted successfully. Slavi C. Sevov, assistant professor of chemistry, and his colleagues, Virginie Quéneau and Evgeny Todorov, heated elemental rubidium and silicon to 900 °C to produce Rb12Si17. They determined this reactive product is composed of Si942 and Si442 anions and Rb+ counterions. The scientists also found that each Si942 cluster differed slightly in shape and angle.