 Dividing by the Avogadro constant gives "V" =  = 0.8685 Å, corresponding to "r" = 0.59 Å.The polarizability "α" of a gas is related to its electric susceptibility "χ" by the relation
and the electric susceptibility may be calculated from tabulated values of the relative permittivity "ε" using the relation "χ" = "ε"–1.The electric susceptibility of helium "χ" = at 0 °C and 101.325 kPa, which corresponds to a polarizability "α" = .