6-(2,3-Dichlorophenyl)-1,2,4-triazine-3,5(2H,4H)-dione|6-(2,3-Dichlorophenyl)-1,2,4-triazine-3,5(2H,4H)-dione ;|6-(2,3-Dichlorophenyl)-1,2,4-triazine-3,5(2H,4H)-dione;|6-(2,32H,4H)-dione, Lamotrigine Impurity D