Symbol Rb Atomic radius: pm 248 Fusion: kJ/Mole 2.19
Name Rubidium Ionic radius: pm (+1)161 Boiling point: C 688
Atomic number 37 Electron affinity 0.49 Melting point: C 39
Atomic weight 85.47 1st  ion potential 4.18 Specific Heat Cap: J/(g K) 0.36
Classification Alkali metal Natural form Solid Thermal Cond: W/(cm K) 0.58
Configuration [Kr]5s1 Crystal structure BCC Electrical Cond 0.0779
Oxidation states 1 Density 1.53 Abundance: mg/kg-crust 90
Electronegativity 0.82 Vaporization: kJ/Mole 69.2    
Rubidium was discovered in 1861 by Robert Bunsen and Gustav Kirchloff. Uses - photocells, catalysts, making special glasses