where α and β are coefficients representing the salt components, c is the concentration of the atomic species, f (Q) is the X-ray form factor, and δ αβ is the Kronecker delta function. The weights w αβ are normalized such that they sum to one for all values of Q. For neutron scattering, the X-ray atomic form factors are replaced with the neutron scattering lengths b that are independent of Q. The superscripts indicate that the structure factor or PDF was weighted using Eq. ( ) for neutrons (n) or X-rays (x). A discrete Fourier sine transform is used to calculate the pair distribution function (PDF) g(r) as