Tl (I)           Tl⁺ + e  <---->  Tl      e^o = -0.3363 v                Radii Tl⁺ = 1.40

Tl (III)      Tl³⁺ + 3e <---->  Tl      e^o = .72 v                       Radii Tl³⁺ = .95                       Atomic Radii  Tl = 2.08

                                Ionization Enthalpies for Tl (KJ mol^-1)

                                                                          1st       589.0

                                                                         2nd     1958.7

                                                                        3rd      2862.8

                                                                          4th      4867.7