There are two equivalent Lewis structures necessary to describe the bonding in SF4O. Both structures involve the bonding of one sulfur atom to three fluorine atoms and to three oxygen atoms tetrahedrally. In one drawing, double bonds connect sulfur to one oxygen and one fluorine; in the second, one of the oxygen’s bonds with sulfur is a multiple bond. However, these multiple bonds can rapidly revert from one oxygen atom to another to produce a symmetrical charge distribution over all four O atoms, rendering these two structures equivalent:

\[:\ddot{\text{O}}-\text{S}(=\text{F})_{2}(\text{=O})_{2} \rightleftharpoons :\ddot{\text{O}}=\text{S}(=\text{F})_{2}(\text{=O})\text{O}^-\]