An identical expression to Einstein's formula for the diffusion coefficient was also found by Walther Nernst in 1888 Zeit. Source: Internet
He writes for the diffusion coefficient k′, where is the osmotic pressure and k is the ratio of the frictional force to the molecular viscosity which he assumes is given by Stokes's formula for the viscosity. Source: Internet
In turbulent flows, the transport by eddy motion can be expressed as a grossly increased diffusion coefficient. Source: Internet
Phys. Chem. 9 (1888) 613. in which he expressed the diffusion coefficient as the ratio of the osmotic pressure to the ratio of the frictional force and the velocity to which it gives rise. Source: Internet
This dependence does not affect Fick's first law but the second law changes: : 2. In anisotropic media, the diffusion coefficient depends on the direction. Source: Internet
For an attractive interaction between particles, the diffusion coefficient tends to decrease as concentration increases. Source: Internet