# What is the anhydride of perchloric acid?

Of $C {l}_{2} {O}_{7} \text{, chlorine heptoxide}$................or $\text{perchloric anhydride}$...........
This is the anhydride of perchloric acid, $H C l {O}_{4}$, i.e. ${O}_{3} C l - O - C l {O}_{3}$; we have $C l \left(V I I\right)$, i.e. the maximum Group oxidation number is expressed.