In general, when the bond distance between two atoms is larger than the sum of their covalent radii, it suggests that the interaction is more likely to be a non-covalent interaction, such as a van der Waals interaction, rather than a typical covalent bond.
In your case, if the bond distance between the Si and O atoms is significantly larger (199 pm) than the sum of their covalent radii (116 pm + 63 pm = 179 pm), it suggests that the interaction is more likely to be a van der Waals interaction rather than a typical covalent bond. However, it is important to note that the classification of an interaction as covalent or non-covalent is not always straightforward and can depend on various factors, including the nature of the atoms involved and the specific molecular environment.
