Any help will be appreciated, 18 Down, Colourless corrosive liquid that occurs naturally in plants and insects, (6 & 4) To me the answer is Folic Acid, or Folate Acid, but this clashes with 25 Across which the answer is 'Impatiens', for the 6 letter word I have 'F???I ?'. I am wondering if Folic has been misspelt with two L's ?