where ⁠ ν ν + ⁠ and ⁠ ν ν − − ⁠ are the numbers of cations and anions respectively per formula unit of electrolyte. In practice the molar ionic conductivities are calculated from the measured ion transport numbers and the total molar conductivity. For the cation λ λ 0 + = t + ⋅ ⋅ Λ Λ 0 ν ν + , and similarly for the anion. In solutions, where ionic complexation or associaltion are important, two different transport/transference numbers can be defined.