Not a whole lot is known about the chemistry of Californium due to its high radioactivity and relative rarity. (It does not occur naturally and has to be made in a nuclear reactor). The pure metal has actually never been made in a visible form, I believe. All I do know about it is that it generally exhibits an oxidation state of +3 in aqueous solutions, and on occasion +2. It is expected to have a similar chemistry to that of Dysprosium which lies directly above it on the Periodic Table. About 3% of the decay of Cf isotopes are due to spontaneous fission, so Cf is a VERY potent neutron emitter. That makes it quite dangerous to work with which would also explain why not a helluva lot is known about it chemically.