Title: Francium
CAS Registry Number: 7440-73-5
Additional Names: Eka-cesium
Literature References: Fr; at. no. 87; valence 1. Group IA (1). No stable nuclides. Naturally occurring isotope: 223, Actinum K, (longest lived isotope, T½ 21.8 min, b- emitter; rel. at. mass 223.0197) formed by a-decay of actinium 227Ac in 235U series. Known artificial isotopes: 201-222, 224-232. Found in uranium minerals. Terrestial abundance ~2 ´ 1018 ppm. Also obtainable by proton bombardment of thorium. First obtained in 1939 from an actinium prepn by Perey, J. Phys. Radium 10, 439 (1939); J. Chim. Phys. 43, 155, 262 (1946); Hyde, Ghiorso, Phys. Rev. 90, 267 (1953); Hyde, J. Am. Chem. Soc. 74, 4181 (1952). Isoln by paper chromatography: Perey, Adloff, Compt. Rend. 236, 1163 (1953). Reviews: Hyde, J. Chem. Educ. 36, 15-21 (1959); Whaley, "Sodium, Potassium, Rubidium, Cesium and Francium" in Comprehensive Inorganic Chemistry vol. 1, J. C. Bailar Jr., et al., Eds. (Pergamon Press, Oxford, 1973) pp 369-529; Chemistry of the Elements N. N. Greenwood, A. Earnshaw, Eds. (Pergamon Press, New York, 1984) pp 75-116.
Properties: Most electropositive element. Chemical behavior similar to that of other alkali metals. |