What element has the lowest electronectivity?

Francuim is thought to have the lowest electro-negativity.

Linus Pauling estimated that francium had the same electro-negativity as Caesium = 0.7. The electro-negativity of caesium was later revised to 7.9 but francium is so unstable and reactive that it is not possible to obtain samples of pure francium to accurately determine its electro-negativity.