The width of a silicon atom is not a well-defined value. Atoms are not solid spheres with a fixed width. Instead, they are more like fuzzy clouds of probability, where the electrons are most likely to be found.

Here's why it's tricky to define:

* Atomic Radius: The concept of "atomic radius" is used, but it's often defined in various ways, such as the covalent radius (half the distance between the nuclei of two bonded atoms) or the metallic radius (half the distance between the nuclei of two adjacent atoms in a metallic crystal).

* Silicon's Structure: Silicon has different crystal structures depending on the environment. This influences how atoms are arranged and the distance between them.

* Quantum Mechanics: The actual size of an atom is better described by the probability of finding an electron at a particular point in space, rather than a fixed boundary.

However, to give you a general idea:

* Covalent radius of silicon is about 0.111 nanometers.

* Metallic radius of silicon is about 0.117 nanometers.

Keep in mind that these are just approximate values and the actual "width" of a silicon atom will vary depending on the specific context.