Keywords: Freunds acid (1,3,6).svg Skeletal formula of Freund's acid 1 3 6 ref to Louis Freund 1883 synonymous with 4-amino-2 7-naphthalenedisulfonic acid Own Created using ISIS/Draw and Inkscape Krakatit 2008-08-31 Naphthalene sulfonic acids Naphthylamines |