The position of Chiron's orbit, placed between Saturn and Uranus, is rather special. In spite of all attempts at classification, Chiron has, as it were, taken on the role of a planet. His path is severely eccentric, like that of Pluto, so that he occasionally crosses the orbits of both Saturn and Uranus. Most astrologers regard him as a sort of "mediator" between these two
http://www.astro.com/astrology/in_chiron_e.htm