a
\(S_8\) : Molecular solid, in solid sulphur various \(S_8\) molecules are bonded to one another by weak molecular forces

(Figure)  \(\Rightarrow \)   Zig -Zag

\(SiO_2\) : represents to \(3D\) silicate, that has covalent lattice as one silicon atom is bonded to four oxygen atoms and each oxygen in turn is bonded to two silicon.

\(\begin{matrix}
   \begin{matrix}
   \begin{matrix}
   \begin{matrix}
   |\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,|  \\
   O\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,O  \\
\end{matrix}  \\
   |\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,|  \\
   -O-Si-O-Si-O-  \\
   |\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,|  \\
\end{matrix}  \\
   \,O\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,O  \\
   \,\,|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,|  \\
   -O-Si-O-Si-O-  \\
\end{matrix}  \\
   |\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,|\,  \\
   O\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,O  \\
   |\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,|  \\
\end{matrix}\)