I (Rmrfstar) believe that the information included in these books should be incorporated into this article ASAP. Unfortunately, they're not easy to find...
- Analytical Chemistry of Technetium, Promethium, Astatine and Francium by Avgusta Konstantinovna. Lavrukhina, Aleksandr Aleksandrovich Pozdnyakov ISBN 0250399237
- The Radiochemistry of Francium by Earl K. Hyde
- The Chemistry of Lithium, Sodium, Potassium, Rubidium, Cesium and Francium by William A. Hart a reprint with corrections of Comprehensive Inorganic Chemistry chapters 7 and 8 (presumably the Sneed edition of 1953; try also CIO 1973, ed. Bailar et al., ISBN 008017275X
Electronegativity: The Pauling scale is the most commonly used system for electronegativity, and most complete electronegativity lists use it. These lists also put francium as the lowest electronegativity with 0.7. However, some of the reported values may be estimated rather than calculated. The Allen scale may be a more complete system, and it places caesium as the least electronegative element. However, it is difficult to find lists of Allen electronegativity values to confirm this. There seems to be no one source which says all of that, so for now, the Pauling value will remain, unless a better source can be found.