Elements of group-15 form compounds in +5 oxidation state. However, bismuth forms only one well-characterised compound in +5 oxidation state. The compound is (i) Bi2O5 (ii) BiF5 (iii) BiCl5 (iv) Bi2S5
Due to the inert pair effect bismuth only exhibit +3 oxidation state and form trihalides. But due to the size and the high electronegativity of Florine, Bismuth forms BiF5 only.
