terephthalylidene dicamphor sulfonic acid [ 3,3'-(1,4-phenylenedimethylidyne)bis(7,7-dimethyl-2-oxobicyclo(2.2.1)heptane-1-methanesulfonic acid),Ecamsule,Mexoryl SX ] structure given in first source; abreviated as TDSA; FDA approved 2006 as component of Anthelios SX along with avobenzone and octocrylene