The valence electron configuration of sulfur S = 3s²3p⁴
Valence electron configuration of Br = 4s²4p⁵
In SBr4, the central Sulfur (S) atom forms 4 covalent bonds with the 4 bromine (Br) atoms. In addition it has 1 lone pair of electrons.
Since the electron geometry not only considers the bond pairs but the lone pairs as well, in the case of SBr4 this would be trigonal bipyramidal.
(Molecular geometry would only consider the 4 covalent bonds which would lend it a distorted tetrahedral structure)
