c5h6o4

from The Collaborative International Dictionary of English v.0.48
Itaconic \It`a*con"ic\, a. [From aconitic, by transposition of
   the letters.] (Chem.)
   Pertaining to, or designating, an acid, {C5H6O4}, which is
   obtained as a white crystalline substance by decomposing
   aconitic and other organic acids.
   [1913 Webster]
    

[email protected]