(R)-1-{(S)-2-[Bis[3,5-bis(trifluoromethyl)phenyl]phosphino]-ferrocenyl}ethyldi(3; (R)-(-)-1-((S)-2-(Di(3,5-bis-trifluoromethylphenyl)phosphino)ferrocenyl)ethyl-di-(3,5-dimethylphenyl)phosphine; (R)-(-)-1-{(S)-2-[Bis(3,5-di-trifluoromethylphenyl)phosphino]ferrocenyl}ethyldi-3,5-xylylphosphine,min.97%; (r,r)-1-{1-[bis(3,5-dimethylphenyl)phosphino]ethyl}-2-{bis[3,5-bis(trifluoromethyl)phenyl]phosphino}ferrocene (acc to cas); (R)-(-)-1-{(S)-2-[Bis(3,5-di-trifluoromethylphenyl)phosphino]ferrocenyl}ethyldi-3,5-xylylphosphine, min. 97%; 1,2,3,4,5-cyclopentanepentayl, compd. with 1-[bis[3,5-bis(trifluoromethyl)phenyl]phosphino]-2-[(1S)-1-[bis(3,5-dimethylphenyl)phosphino]ethyl]-1,2,3,4,5-cyclopentanepentayl, iron salt (1:1:1)