The silicates having chain and cyclic structures involve:

discrete $Si{O}_{\mathit{4}}^{\mathit{-}\mathit{4}}$ tetrahedral

sharing of one oxygen atom between two $Si{O}_{\mathit{4}}^{\mathit{-}\mathit{4}}$ tetrahedral units

sharing of two oxygen atoms of each $Si{O}_{\mathit{4}}^{\mathit{-}\mathit{4}}$ tetrahedral unit with two other tetrahedral units

sharing of three oxygen atom of each $Si{O}_{\mathit{4}}^{\mathit{-}\mathit{4}}$ tetrahedral unit with three other tetrahedral units