Why SiO2 crystal is atomic crystal rather than molecular crystal

In the silicon dioxide crystal, four oxygen atoms around one silicon atom form a regular tetrahedron, and silicon is in the center of the regular tetrahedron. At the same time, one oxygen atom forms a covalent bond with two silicon atoms, forming a spatial network structure, and there is no silicon dioxide molecule. So it's an atomic crystal.
A crystal with a spatial network structure formed by strong covalent bonds between adjacent atoms is called an atomic crystal.
In such crystals as atomic crystals, the particles on the lattice are atoms, and the atoms are bound together by covalent bonds. Such crystals are called atomic crystals. Such as diamond crystal, simple silicon, silicon dioxide, etc. are atomic crystals.