Elements of group- 15 form compounds in +5 oxidation state. However, bismuth forms only one well characterized compound in +5 oxidation state. The compound is

BiF5 is a stable molecule and its very abnormal about its existence. For Bismuth, the +3 oxidation state is more stable than +5 oxidation state due to inert pair effect. However, since F is the most electronegative element in the periodic table, it can stabilise Bi+5 ion.