any of various oxyacids of iodine containing a greater proportion of oxygen than iodic acid and differing from each other in water content, esp either of the crystalline compounds HIO4 (metaperiodic acid) and H5IO6 (paraperiodic acid)
Word origin
C19: from per- + iodic
periodic acid in American English
(ˌpɜraɪˈɑdɪk)
a white crystalline solid, HIO4, formed by careful oxidation of iodine or iodic acid: it is a strong oxidizing agent