C,C'-azodi(formamid)
a kyselina 2-(4-a, b-dihydroxy-c-[5-(fenylaminosulfonyl)-2-hydroxyfenyldiazenyl]fenyldiazenylfenylamino)-5-nitrobenzénsulfónová, kde a = 2, b = 6, c = 3 alebo a = 2, b = 4, c = 5 alebo a = 3, b = 5, c = 2