Center letter: o
Outer letter: a d i n t x
Answers (37):
  antioxidant
  oxidant
  oxidation
  addition
  anion
  annatto
  annotation
  anoint
  anon
  anoxia
  antitoxin
  axon
  dino
  dioxin
  ditto
  dodo
  donation
  doodad
  doxx
  idiot
  initiation
  into
  intonation
  iota
  nation
  noon
  notation
  notion
  onion
  onto
  tattoo
  taxation
  taxon
  toad
  toon
  toot
  toxin