Berkelium(III) fluoride is a binary inorganic compound of berkelium and fluorine with the chemical formula BkF3.

[1][2][3] The compound can be prepared by treating Bk2O3 with a gaseous mixture of H2 and HF at 600 °C.

[4] Berkelium trifluoride forms a yellow-green solid with two structures.

At high temperature, it is trigonal (LaF3 structure), with lattice parameters a = 697 pm and c = 714 pm.

[6][7] Berkelium trifluoride is reduced by lithium to obtain metallic berkelium: