There are two other measures of susceptibility, the molar magnetic susceptibility (χ m) with unit m /mol, and the mass magnetic susceptibility (χ ρ) with unit m /kg that are defined below, where ρ is the density with unit kg/m and M is molar mass with unit kg/mol: χ χ ρ ρ = χ χ v ρ ρ ; χ χ m = M χ χ ρ ρ = M ρ ρ χ χ v .