Californium(IV) oxideCalifornium oxide is a binary inorganic compound of californium and oxygen with the formula.SynthesisCalifornium dioxide is produced by oxidizing californium with molecular and atomic oxygen at high pressure.Physical propertiesCalifornium oxide is a black-brown solid that has a cubic fluorite crystal structure with a lattice parameter, the distance between unit cells in the crystal, of 531.0 ± 0.2 pm.