What is "silsesquioxane"

n. (context chemistry English) Any chemical compound with the empirical chemical formula RSiO_1.5, where ''R'' is either hydrogen or an alkyl, alkene, aryl or arylene group.

200px|thumbnail|right|A cubic silsesquioxane. A silsesquioxane is an organosilicon compound with the chemical formula [RSiO] (R = H, alkyl, aryl or alkoxyl). Silsesquioxanes are colorless solids that adopt cage-like or polymeric structures with Si-O-Si linkages and tetrahedral Si vertices. Silsesquioxanes are members of polyoctahedral silsesquioxanes ("POSS"), which have attracted attention as precursors to ceramic materials and nanocomposites. Diverse substituents (R) can be attached to the Si centers. The molecules are unusual because they feature an inorganic silicate core and an organic exterior. The silica core confers rigidity and thermal stability.