Silsesquioxane ($(\mathrm{RSi}{\mathrm{O}}_{3/2}{)}_{\mathrm{n}}$)

A silicon–oxygen framework with ideal fully condensed composition $(\mathrm{RSi}{\mathrm{O}}_{3/2}{)}_{\mathrm{n}}$. Each silicon has one organic substituent and three siloxane bridges. Incompletely condensed cages retain silanol groups.

A corner-deficient cage ${\mathrm{R}}_7\mathrm{S}{\mathrm{i}}_7{\mathrm{O}}_9(\mathrm{OH}{)}_3$. Removing one silicon corner from a T8 cage leaves three silanol-bearing silicon sites, three further sites adjacent to those, and a unique opposite site: symmetry classes 3:3:1.

A cage ${\mathrm{R}}_{10}\mathrm{S}{\mathrm{i}}_{10}{\mathrm{O}}_{15}$ with a common pentagonal-prismatic silicon skeleton and an oxygen bridge on each edge.

A cage ${\mathrm{R}}_8\mathrm{S}{\mathrm{i}}_8{\mathrm{O}}_{12}$ represented by a cube of eight silicon vertices with one bridging oxygen on each of twelve edges.