The molecule is trianion of (1E)-4-oxobut-1-ene-1,2,4-tricarboxylic acid arising from deprotonation of all three carboxylic acid groups. It is a conjugate base of a (1E)-4-oxobut-1-ene-1,2,4-tricarboxylic acid.
(E)-4-oxobut-1-ene-1,2,4-tricarboxylate