Account for the following
`SF_6` exists but `OF_6` does not, though both oxygen and sulfur belong to the same group in the periodic table.

Explanation

Though oxygen and sulphur belong to the same group, but they lie in the second and third period of the periodic table respectively.
Electronic configuration os `S(16):1s^(2)2s^(2)2p^(6)3s^(2)3p^(4)3d^(0)`.
In this, valence shell contains 6 valence elctrons with vacant d-orbitals. Therefore, it exhibits covalency of 6 resulting in the formation of `SF_(6)`.
electronic configuration of `O(8):1s^(2)2s^(2)2p^(4)`.
as vacant d orbital is absent, it shows maximum covalency of 2. Therefore, it unable to form `OF_(6)`