# Which material is structurally distinct: graphite; silicon dioxide; or propane?

Graphite is a non-molecular structure, that features $C - C$ bond angles of 120""^@. While there are 120""^@ bonds in acetic acid, there are 2 rather than 3 such bonds. Propane and silicon dioxide are base on tetrahedra. Of course propane is MOLECULAR, whereas the other materials are NON-MOLECULAR.