a. [mod. f. Gr. ἀλλοφανής (see prec.) + -IC.] Of or pertaining to anything which changes color or appearance; as Allophanic Acid C2H4N2O3, a monureide of carbonic acid only known in the form of salts or ethers.
1863. Watts, Chem. Dict., I. 132. By passing the vapour of cyanic acid into absolute alcohol, Liebig and Wöhler obtained in 1820 a peculiar ether … the ether of a peculiar acid which they called allophanic acid. Ibid., I. 133. Allophanate of Ethyl or Allophanic Ether, C4H8N2O3.
