Complex sentence: The reaction initially produces permanganic acid, HMnO 4 (structurally, HOMnO 3), which spontaneously loses water to form its anhydride, Mn 2 O 7.
Split into simpler sentences: The reaction initially produces permanganic acid, HMnO 4 (also described with the formula HOMnO 3). Permanganic acid spontaneously loses water to form its anhydride, Mn 2 O 7.