Californium Californium Californium is a radioactive chemical element with symbol Cf and atomic number 98. The element was first synthesized in 1950 at the Lawrence Berkeley National Laboratory (then the University of California Radiation Laboratory), by bombarding curium with alpha particles (helium-4 ions). It is an actinide element, the sixth transuranium element to be synthesized, and has the second-highest atomic mass of all the elements that have been produced in amounts large enough to see with the unaided eye (after einsteinium). The element was named after the university and the state of California. Two crystalline forms exist for californium under normal
Californium compounds +3 oxidation states include the sulfide and metallocene. Californium(IV) oxide (black brown, CfO), californium(IV) fluoride (green, CfF) represent the IV oxidation state. The II state is represented by californium(II) bromide (yellow, CfBr) and californium(II) iodide (dark violet, CfI). Californium(IV) oxide (CfO) is a black-brown solid that has a cubic crystal structure with a lattice parameter, the distance between unit cells in the crystal, of 531.0 ± 0.2 pm. Crystals of californium(III) oxide normally have a body-centered cubic symmetry. They convert to a monoclinic form upon heating to about 1400 °C and melt at 1750 °C. Californium(III) chloride (CfCl) is an