`SF_(6)` is a well known compound while `SH_(6)` does not exist. Explain.

Explanation

Sulphur atom has a very small size. Therefore, six chlorine atoms cannot be linked with an atom of sulphur whereas six fluorine atoms can be linked because of smaller size. Moreover, chlorine being less electrongegative than fluorine cannot cause the promotion of electrons in the vacant d-orbitals as effectively as done by fluorine because of its higher electronegativity.