Table 3.

Values and definitions of properties of astatine derived from the EA and IE.

Property	Definition	Value
Electron affinity	EA	2.41578(7) eV
Ionization energy	IE	9.31751(8) eV12
Electronegativity	${\chi }_{\mathrm{M}}=\frac{\mathrm{IE}+\mathrm{EA}}{2}$	5.86665(7) eV
Hardness	$\eta =\frac{\mathrm{IE}-\mathrm{EA}}{2}$	3.45087(7) eV
Softness	$S=\frac{1}{2\eta }$	0.14489(2) eV−1
Electrophilicity	$\omega =\frac{{\chi }_{\mathrm{M}}^2}{2\eta }$	4.98680(16) eV