Sulfur tetrafluoride, or SF4, is a polar compound. The SF4 molecule contains four covalent bonds and a non-bonded pair of electrons, as illustrated by the University of Wisconsin-Platteville.
As the University of Wisconsin-Eau Claire notes, the S-F bond is considered polar because of a significant difference in electronegativity between sulfur and fluorine. As stated by Elmhurst College, there is a direct correlation between the polarity of a molecule and the number, type and geometry of the bonds present. As a non-bonded pair of electrons is considered to be a bond, SF4 has five bonds and follows a trigonal bypiramid geometry. SF4 is polar because a non-bonded pair of electrons doesn't have the same electronegativity as a fluorine atom.